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SERV1775January 2004

TECHNICAL PRESENTATION

953C/963C TRACK LOADERS WITHTIER II ENGINES

INTRODUCTION

Meeting Guide 775

SERVICE TRAINING

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953C/963C TRACK LOADERS WITHTIER II ENGINES - INTRODUCTIONSERV1775

AUDIENCELevel II–Service personnel who understand the principles of machine systems operation,diagnostic equipment, and procedures for testing and adjusting.

CONTENTThis presentation provides update information on machine components and system operation ofthe power train hydraulic system and the implement hydraulic system, for the 953C and 963CTrack Loaders with Tier II Engines. This presentation may be used for self paced and selfdirected training.

OBJECTIVES

After learning the information in this presentation, the technician will be able to:

1. locate and identify the new components on the 953C and 963C Tier II Track Loaders;2. explain the operation of the components in the systems; and3. trace the flow of oil through the systems.

REFERENCES

"953C/963C/973C Track Loaders–Implement Hydraulic System" SERV2695"'C" Series Track Loaders–Power Train'" SERV2694STMG 735 "973C Track Loader–Introduction" SERV1735"'C" Series Track Loaders–Power Train Calibration'" SEVN4937STMG 724 "963C Track Loader" SERV1724953C Track Loader Specalog AEHQ5541963C Track Loader Specalog AEHQ5542

Estimated Time: 3 HoursIllustrations: 74Handouts: 17Form: SERV1775Date: 1/04

© 2004 Caterpillar Inc.

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TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5

OPERATOR'S STATION..............................................................................................................9

SERVICE COMPARTMENTS AND AREAS ...........................................................................23Engine ...................................................................................................................................33

HYDRAULIC SYSTEMS..........................................................................................................40963C Power Train Hystat Hydraulic System .......................................................................51953C Power Train Hystat Hydraulic System .......................................................................67963C Implement Hydraulic System .....................................................................................83

ADVANCED OPTIONAL SYSTEMS.......................................................................................95

SIGNIFICANT MAINTENANCE CHANGES .........................................................................98

NEW TOOLING/SKILLS REQUIRED FOR SERVICE ..........................................................99

CONCLUSION.........................................................................................................................100

HYDRAULIC SCHEMATIC COLOR CODE.........................................................................101

HANDOUTS.............................................................................................................................102

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NOTES

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SINTRODUCTION

Caterpillar is introducing updated 953C and 963C Track Loaders with a new electronicallycontrolled engine. The updated 953C is powered by a Caterpillar 3126B, six-cylinder diesel engine, rated at 95 kW (129 hp) at 2000 rpm. The 953C Track Loader weighs 15 145 kg(33,389 lbs.).

The updated 963C is powered by a Caterpillar 3126B, six-cylinder diesel engine, rated at 118kW (158 hp) at 2000 rpm. The 963C weighs 19 589 kg (43,194 lb.)

The updated machines retain the same nomenclature as the previous machines they arereplacing. The work tools, buckets, ripper-scarifier, and GET are unchanged from the formermodels.

The machines have an updated instrument panel to provide additional machine operatinginformation to the operator. The machines retain the rear-mounted engine, box-section integral frame, electronically-controlled hydrostatic drive system, and the Z-barloader linkage. It is designed for improved operator comfort, serviceability, operating costs,reliability, and durability.

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953C/963C TRACK LOADERSWITH TIER II ENGINES

INTRODUCTION

© 2004 Caterpillar Inc.

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The 3126B engine provides more power than the 3116 engine it replaced. The 3126B enginehas: Hydraulic-actuated Electronic Unit Injectors (HEUI), an air to air aftercooler (ATAAC),three valves per cylinder, and a turbocharger. The engine is controlled and monitored by anAdvanced Diesel Engine Management – Electronic Control Module (ADEM III), whichcontrols all major engine functions and regulates the HEUI. The new engine arrangement willmeet all known emission requirements at the time of introduction, including US EPA Tier IIand European Union Stage 2 regulations.

The electronically controlled hydrostatic drive system automatically matches machine travelspeed to the combined travel and implement loads on the machine enabling maximum travelspeed up to the speed selected by the operator.

The hydrostatic drive train also offers independent power and control of each track, with fastacceleration, infinitely variable speeds, and automatic, on-the-go, direction changes for eachtrack. The operator can command smooth "power turns" or even counter-rotation of the tracksby simply pushing one of the steering pedals. The Caterpillar hydrostatic drive systemmanages itself, freeing the operator to concentrate on using the track loader's superb agility,speed, and maneuverability to do more productive work.

The Z-bar linkage, which is unchanged from previous models, provides high breakout force forfast, easy loading, even from a "hard bank" of highly compacted material. The single, center-mounted tilt cylinder means fewer pivot points to maintain and a better view to thebucket corners, for high operator efficiency.

Improvements have also been made to several systems to enhance customer value.

NOTE: The "HYDRAULIC SCHEMATIC COLOR CODE" is located after the"CONCLUSION" of this presentation.

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SThe cab is designed for visibility, operator comfort, and convenience. The standard ROPS cabis sound suppressed, sealed, pressurized, air conditioned, and resiliently mounted to the frame.A fully adjustable air suspended seat, with side-to-side shock absorption, provides maximumoperator comfort. Conveniently placed switches, gauges, information display, and controlsimprove operator comfort, awareness, and efficiency.

The steel roof is now standard. The rugged steel roof resists bending and tearing, and can beeasily repaired.

The Caterpillar Monitoring System continuously monitors all important engine, implementhydraulic, and hydrostatic drive functions. The system permits fast troubleshooting, resulting inincreased track loader availability and reduced downtime for repairs. The monitoring system isflashable using Caterpillar Electronic Technician (Cat ET).

The cab improvements include:- new dash with a flashable monitoring system- rocker switch parking brake control and rocker switch throttle control- new fuse panel - improved sealing- improved defrost- improved armrests

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The updated machines are now equipped with electronic engines featuring a new coolingsystem. The radiator grill swings out. Rated engine speed has been reduced to 2000 rpm from2200 rpm. The 963C features remote oil filters and an under the hood muffler. The starter hasbeen improved and the machines feature a brushless alternator.

The undercarriage features larger track links and tough steel sprocket segments. A new optionalattachment on the 953C and 963C is the Rotating Bushing Track (RBT).

Due to the change in rated engine speed the implement pump size was increased to provide thesame flow rate at 2000 rpm as the smaller pump did at 2200 rpm.

The power train pumps remained the same. The gear ratios in the splitter box have changed tocompensate for the change in engine rpm.

Hystat Calibrations can be done through Caterpillar Electronic Technician (Cat ET).

Maintenance intervals have been increased to 500 hours for the engine oil, engine oil filter, andfuel filters, reducing the cost and time required for engine maintenance. A number of othermaintenance intervals have also been increased.

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SOPERATOR'S STATION

The 953C and 963C offers a premium quality seat as standard equipment. This seat, with clothupholstery in cab-equipped machines (vinyl upholstery in open canopy machines), isergonomically designed and fully adjustable for maximum operator comfort. The seat issuspended on a cushion of air and equipped with a special side-to-side "isolator" to support theoperator and absorb vibrations. When the isolator in in the unlocked position the seat willfunction much like a shock absorber, dampening left to right seat motion. The isolator seat isequipped with an extra control (not shown) on the left side of the seat above the slide railadjustment lever.

Cushion side-bolsters on the seat help the wide safety belt keep the operator centered in the seatwhen working on side slopes and rough terrain. The backrest conforms to the operator's spinalcurve and features adjustable recline angle and lumbar support. The removable headrest hasvertical and tilt adjustments.

The retractable seat belt is 75 mm (3 in) wide for comfortable restraint. The automaticretraction mechanism keeps the belt off the floor when not in use.

The height of the armrests is easily adjusted. Total adjustability lets the operator customize thearmrests to the most comfortable position. The right armrest is adjustable: up, down, forward,and backward.

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SOn the left console is the horn (1), engine speed selector switch (2), Work-Travel Mode(turtle/rabbit) switch (3), parking brake switch (4), and travel speed and direction control lever (5).

The operator controls engine speed (rpm) by using an electronic engine speed selector switchwhich is a "rocker" switch located on the left console. The Engine ECM will always start theengine at low-idle. When the operator chooses to increase the engine rpm, the operator mustpress the upper (rpm increase) side of the switch.

Pressing the rpm increase side of the switch once, for less than one second, will cause theengine rpm to go to high-idle. Pressing and holding the rpm increase side of the switch forlonger than one second will increase the rpm (in increments of 200 rpm), at the rate of about400 rpm per second. It will take 3 to 5 seconds for the operator to go from low-idle to high-idle by holding the switch. The rpm decrease side of the switch works the same way whenreducing the rpm of the engine. Any time the electronic engine speed selector switch isactivated to change the rpm of the engine, the Electronic Message Display will automaticallyswitch to the Digital Tachometer Mode for 15 seconds to show engine rpm.

At customers’ requests, a Work-Travel Mode switch was added to the dashboard on the formermodels. On the current machines, this Work-Travel Mode switch is located on the operator’sleft control console, within easy reach. The operator can change the turtle/rabbit command anytime. Regardless of any change in the turtle/rabbit command, the Power Train ElectronicControl Module (ECM) will not change the travel mode until the speed and direction controllever is returned to the NEUTRAL position.

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The operator can choose between two operating modes.

1. In Travel Mode (Rabbit), the Power Train ECM retains the standard speed features formachine operations.

2. In Work Mode (Turtle), the Power Train ECM limits the maximum speed of the trackloaders to 6.6 km/h, (4.1 mph), which is 67% of the machine’s maximum rated speed.

The Work Mode offers the following advantages:

- When working in tight areas, choosing the Work Mode offers a lower overall speed rangeof the speed/direction lever allowing more precise control of the machine.

- When in Work Mode, limiting the machine maximum speed reduces wear ofundercarriage components, lowering the owning and operating costs of the machine.

If the machine owner requests it, the dealer can reduce the top speed the machine will travel ineither FORWARD or REVERSE while in the Travel (Rabbit) and Work (Turtle) Modes. If jobconditions indicate a slower maximum speed would be desirable or the owner prefers to lowerthe top speed of reverse to reduce undercarriage wear, the Power Train ECM can be set to alower maximum speed. Speed reductions programmed into the Power Train ECM reducemaximum speeds in both the Work Mode and the Travel Mode by the same percentages.

The parking brake switch on the left console, is for the operator to use to apply the parkingbrakes after the machine is stopped. If this switch is moved to the "BRAKE-ON" positionwhile the machine is moving, the Power Train ECM will quickly bring the machine to acontrolled stop. If the switch is moved to the "BRAKE-OFF" position while the speed anddirection control lever is in a forward or reverse position, the Power Train ECM will preventthe machine from moving until the speed and direction control lever is first moved to the zerospeed position, and then moved to command a speed and direction.

The travel speed and direction control lever (5) is connected to a position sensor thatcontinuously signals the position of the lever to the Power Train ECM. The sensor detectsthree different lever positions: FORWARD, NEUTRAL, AND REVERSE. When thespeed/direction lever is in the reverse direction side of the control, the back-up alarm willsound. The Power Train ECM uses the signal from the sensor to determine which steeringsolenoid valves to activate and how far to open them. The sensor changes its signal as the leveris moved farther from the brakes-on position into FORWARD on the "reverse V" or intoREVERSE on the "reverse V" indicating the operator wants to travel at a faster speed in thechosen direction. Technicians can adjust the control sensitivity of the speed and directioncontrol lever using Cat ET.

When the engine is started, the ADEM III controller interfaces with the Power Train ECM todetermine if the parking brake switch is in the "BRAKE-ON" position and the speed anddirection control lever is in the "BRAKE-ON" position in the "reverse V" pattern. Either theparking brake switch or the speed and direction lever must be in the "BRAKE-ON" position forthe ADEM III controller to start the engine. The speed and direction lever must be returned tothe NEUTRAL position and then shifted again for the machine to move. The recommendationis to have both controls in the "BRAKE ON" position when starting.

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SThe fuse panel (1) along with the alternator breaker (2) have been relocated to the inside of thecab, behind the trim panel under the speed and direction control lever.

The fuse panel cover has been removed.

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The dash and instrument panel provide all necessary functions and information within theoperator’s normal line of sight. The Caterpillar Monitoring System constantly monitors all vitalfunctions and alerts the operator to the nature and severity of any abnormalities. Themonitoring system includes:

- four gauges (1)- ten alert indicators (2)- Numeric Message Display (3)- action warning light (4)- low fuel and low coolant warning (5)- action alarm horn (not shown)- key start/stop switch (anti-theft feature is optional) (6)- switch for selecting the information to be shown on the Numeric Message Display (7)- parking brake-on warning light (8)- light switches (9)- front - wiper/washer control (10)- rear - wiper/washer control (11)

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The four-gauge display includes engine coolant temperature (1), pump drive oil temperature (2),hydraulic tank oil temperature(3), and fuel level (4).

The monitoring panel has ten alert indicators (5) and the Numeric Message Display (6). Theten alert indicators used are (left to right, top row first):

- low fuel pressure from the transfer pump to the injection pump- case drain filter bypass- charge filter bypass- pump drive oil temperature; indicates the pump drive oil temperature is too high.- charge pressure; indicates low hystat charge oil pressure - engine oil pressure; indicates low engine oil pressure- check engine; indicates a warning is being sent from the ADEM III engine control- electrical charging; indicates the alternator voltage is too high or too low- hydrostatic drive system warning; indicates the Power Train ECM is sending a problem

signal to the Caterpillar Monitoring System- Air Inlet Heater (AIH); flashes when the air inlet heater is activated. The air inlet heater

is standard and operates automatically if needed when the engine is started.

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The Numeric Message Display provides the operator or service technician with specificmachine information. The operator mode switch (7) located on the dash panel, to the right ofthe monitoring lights, is for use by both the operator and service technician. Activating thisswitch will scroll the Numeric Message Display from the default mode (hour meter), enginerpm, override pressure, and odometer.

The monitoring system performs a self-test to verify that the main display module is operatingproperly every time the key start switch is turned from the "OFF" to the "ON" position. Theinternal circuits and the indicators (gauges, action lamp, and action alarm) are automaticallychecked and the main warning light module performs an automatic self-test. The operator mustobserve the outputs to determine whether or not the modules and the outputs are operatingproperly. The Caterpillar Monitoring System returns to its normal mode of operation followingthe test. The tests are as follows:

Main Cluster:

- Each function monitored by the Numeric Message Display will turn on for approximatelyone second. The display will then return to default mode: hour meter.

- All warning lights will flash for one second. Then the indicators will function accordingto the inputs.

Gauge Cluster:

- The pointers will move toward the straight up position within the first one-half second.

- The pointers will move to the far left position within the next second.

- The pointers will move to the far right position within the next one and one-half seconds.

- The pointers will move to the actual monitor position based on the inputs within the nextone-half second.

Monitoring/Alarm Cluster:

- The action alarm horn will sound for approximately one second.

- The action warning lamp will light for approximately three seconds.

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SWhen in Service Mode, service codes from the MAC-14 Electronic Hydrostatic Control (EHC)or Power Train ECM will be shown on the monitoring system Numeric Message Display. Theservice code information is transferred via the Cat Data Link from the Power Train ECM to themain display module. The diagnostic information is shown when the main display module is inService Mode. The Module Identifier (MID) indicates which electronic control module issending the service code.

Three service switches

- service switch (1)

- clear switch (2)

- sensor/speed calibrate switch (3)

When a sensor fault is present, the corresponding warning for that sensor is also activated forthe operator. For example, if the signal wire for the pump drive temperature sensor is shorted,then:

a. the corresponding service code is stored in memory.

b. the gauge for pump drive temperature is displayed in the warning range.

c. the action lamp flashes.

With the Service Mode switch, located below the operator’s right arm rest in the "Service"position, a service technician can troubleshoot the Caterpillar Monitoring System by using theOperator Mode switch on the instrument panel to view specific machine information.

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Service codes from the Power Train ECM and the Engine ECM will be displayed on theNumeric Message Display. The service code information is transferred via the Cat Data Linkfrom the Power Train ECM and the Engine ECM to the main display module.

The operator/service technician scrolling switch is on the right side of the instrument panel,above the key. Activating the switch, with the Service Mode switch tuned on, will scrollthrough any diagnostic/service fault codes and present the fault codes on the Numeric MessageDisplay. Normally this switch would scroll through the hour meter, engine rpm, overridepressure, and odometer for the operator.

Service codes from all systems are shown whether a fault (service) code is currently present oroccurred in the past. When the Numeric message displays "Service Code" text is on, the faultcurrently being shown is present in the machine. If the fault code is coming from the memoryof the Caterpillar Monitoring System, not currently present, the "Service Code" is off.

The Service Modes are as follows:

Mode 1 (Harness Code Mode) shows the machine model on which the monitoring system isinstalled.

Mode 2 lets the service technician scroll through each individual gauge.

Mode 3 shows the diagnostic codes for existing or previous problem codes stored in thesystem. Three dashes (---) indicates no code or problem is present for that mode. If thewarning light on the Caterpillar Monitoring System panel is on when a code is displayed, thefault is active. If the warning light on the Caterpillar Monitoring System panel is off when acode is displayed, the fault is in the system memory. After the fault has been repaired, the clearswitch is used to remove the code from the system.

Mode 4 is the "Tattletale Mode" which stores the "worst case" position of each gauge and theinformation displayed by the Numeric Message Display. In this mode, the CaterpillarMonitoring System will show the extreme value for each machine condition monitored. Whenin this mode, each gauge in the four-gauge cluster displays its highest or lowest recordedposition, and highest numeric values will appear on the Numeric Message Display. The clearswitch will reset the system. A fifth "Ghost" gauge for the engine oil pressure is stored in theCaterpillar Monitoring System memory. When the service technician scrolls through theTattletale readings, the lowest engine oil pressure will be presented along with the other gaugereadings.

Mode 5 is the Calibration Mode, which has multiple submodes for calibrating variouscomponents in the hydrostatic drive system.

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SThe operator steers the track loader by depressing the left (1) or right (2) steering pedal. Thecenter brake pedal (3) is used to decrease the speed of the machine, assist in reducing rollback,and hold the machine in position by causing the parking brakes to engage.

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SThe standard operator control for the two hydraulic circuits which operate the lift arms andbucket, is a single "joystick" lever (1) on the console to the operator’s right.

- Forward and back movement lowers and raises the lift arms.

- Left and right movement tilts the bucket back and dumps it.

A second lever (2) is mounted to the right of the single lever control if the machine is equippedwith an attachment implement hydraulic circuit. This lever and circuit is used to control andpower the clamping feature of the multi-purpose bucket or to raise and lower the ripper. If bothan MP bucket and a ripper are installed, a manual diverter valve, controlled by a push-pullcable and handle, is located just behind the second lever. The diverter valve will direct oil toeither the MP bucket or the ripper.

Below the control levers are the pilot valves. When a control lever is shifted, pilot oil isdirected to shift the implement control spools. Pilot controls provide low lever efforts for theoperator.

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Simultaneous lifting and dumping of the bucket is possible with either the single lever or two-lever configuration due to the design of the main control valve group. Simultaneous liftand dump makes it possible for the operator to begin dumping the bucket as it rises above theside of a truck for faster cycle times and increased productivity.

The simultaneous lift and dump feature also lets the operator precisely dump material from thebucket as the bucket is being raised while the machine is spreading fill material to level andgrade an area of ground for a smooth, finished surface.

If the operator pulls the lift lever all the way to the rear (lift detent position), an electro-magnetholds the lever in this "detent position," and the lift arms go up. Power to the electro magnet isstopped when the lift arms rise to the preset height. The lift arms stop raising and the leverreturns to the hold position.

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SA two lever control is available as an attachment.

Forward and back movement of the inboard lever (1) lowers and raises the lift arms. Forwardand back movement of the middle lever (2) tilts the bucket back and dumps it. In the two-leverconfiguration, the track loader dump lever operates in the opposite direction of a wheel loader.Pull back on the bucket lever to dump. Push the lever forward to curl the bucket back.

This outboard lever (3) and circuit is used to control and power the clamping feature of themulti-purpose bucket or to raise and lower the ripper.

The push-pull lever (4) is used to manually operate the diverter valve.

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SThe Heating/Ventilation/Air Conditioning (HVAC) controls are on the far right of the operator'sseat. One of the controls is for the fan (1) and the other (2) controls the temperature.

Air conditioning is now standard on machines with cabs. A heater is standard on canopy-equipped machines. Both the air conditioner and the heater deliver filtered, pressurized,temperature-controlled air to the operator and/or windows. There are 10 louvered vents in thecab, with two on each door-post, for complete air circulation within the operator station. Thecab pressurization filter offers the same filtering capacity as the previous machines.

Access to the diagnostic connector (3) is obtained by opening the right side storagecompartment. A 12 Volt outlet (4) and power inverter (5) are also located in this compartment.

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SSERVICE COMPARTMENTS AND AREAS

The updated 953C uses a 234 L (62 gal) corrosion-proof, non-metallic, fuel tank. This sturdytank is nestled deep within the steel frame and loader tower structure of the 953C for maximumprotection. The lockable fuel filler cap (arrow) is accessible from between the loader armsabove the tank. The fuel tank water and sediment drain is located on the front of the machinebehind an access door.

The fuel tank has the same capacity of the previous 953C.

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SThe hydrostatic power train and the implement hydraulic system share a common hydraulictank on the 953C. It is located between the loader towers, next to the fuel tank, in the front ofthe machine. The tank is sealed and pressurized to prevent contamination from dirt and dustand to provide a positive flow of oil to the implement and hydrostatic pumps. Implementhydraulic oil passes through a screen as it leaves the hydraulic tank, before going to theimplement pump. Oil returning from the implement system flows through two drain filters onthe front of the tank before it enters the tank.

The operator or service technician should check the sight gauge on the hydraulic tank, daily, toconfirm the quantity of oil in the system. When checking the hydraulic oil level sight gauge (1), the bucket must be flat on level ground and the ripper tips lowered to the ground. Ifadditional oil is required, the fill cap (2), should be removed slowly because the hydraulic tankmight be pressurized. The hydraulic oil temperature sensor transmits a signal to the monitoringsystem.

The service interval for the hydraulic oil filter (3) is 1000 hours or 1 year and the hydraulic oilis 4000 hours or 2 years.

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SThe 963C hydraulic tank is located in the same location as the 953C. The sight gauge (1) onthe 963C can be seen from ground level on the right side of the machine along with the fuel fillcap (2).

The capacity of the updated 963C fuel tank is the same 315 L (83.2 gal) as the former 963Ctank. The 963B tank held 19 L (5 gal) less fuel than the 963C tank. The fuel tank is located inthe front of the machine between the loader towers and behind the hydraulic tank.

The new fuel tank is made of 5 mm (0.20 in) thick steel plate rather than the 3 mm (0.12 in)plate used on the previous 963C. The fuel tank reinforcement straps are now on the inside.Welding procedures have been changed to eliminate stress points. The 963C has a manualpump for removing water and contaminates from the bottom of the tank.

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SThe engine radiator (1), air to air aftercooler (ATTAC) (2), and hydraulic oil cooler (3) areincorporated into a single cooling unit at the rear of the machines. By locating the coolingsystem in the rear of the loader, they are away from dust and debris stirred up by the bucketwhile the machine is working.

The radiator uses a copper core cooler with seven rows of tubes and nine horizontal fins perinch. For the engine cooling system, Extended Life Coolant (ELC) is standard. The ELCshould be changed every 6000 hours instead of 3000 hours for a traditional coolant. CoolantExtender should only be added every 3000 hours or 2 years. This dramatically decreasescooling system maintenance time and cost.

The hydraulic oil cooler, located next to the engine radiator, is an aluminum, barplate core, oil-to-air cooler, with six horizontal fins per inch.

The air to air aftercooler (ATAAC) is a single pass, steel, heat exchanger or cooling system forthe air coming from the turbocharger, before it enters the intake manifold.

The pre-cleaner bowl (4) for the engine air intake system is located directly behind theoperator’s station. The bowl should be emptied when the dirt reaches the "full" mark.

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A manual, fuel priming pump (1) is located between the fuel tank and the combined waterseparator/primary fuel filter (2) behind access doors on the right side of the enginecompartment. An electric fuel priming pump is available as an option. After passing throughthe water separator/primary filter, the fuel flows to the fuel transfer pump which pumps itthrough the secondary, high efficiency, fuel filter (3) before it flows to the cylinder head and theinjectors. The dual fuel filter, water separator design, provides protection to the injectionsystem against low-quality or contaminated fuel.

The fuel supply shutoff valve (4) is located near the primary fuel filter/water separator on theright side of the machine.

Also shown are the pump drive dipstick (5), pump drive fill tube (6), case drain filter (7) on the963C, Product Link ECM (8), and disconnect switch (9).

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The hydraulic oil filters are located on the right side of the machine behind the forward accessdoor. The 953C is equipped with two case drain filters (1 and 2). The 963C only has one (1)case drain filter. The hydraulic fluid for the hydrostatic drive system first passes through ascreen when it leaves the tank before it goes to the charge pump (charge pumps on the 963C).From the charge pump, oil flows through a five micron charge oil filter (3) before going intothe hydrostatic drive system and the pilot system for the implement controls. The oil is filteredagain when it returns from the pump and motor case drains, before returning to the tank throughthe case drain filters (27 micron).

If the oil is very cold or if the charge system filter is restricting the flow of oil due tocontamination, a bypass valve contained within the charge oil filter housing will open, directingfluid back to the hydraulic tank. The bypass limits the maximum differential pressure acrossthe filter. When the maximum differential is exceeded, the Power Train ECM will prevent themachine from moving until the differential pressure is below the bypass limit. The monitoringsystem provides input into the Power Train ECM as to the status of the bypass switch.

This filter also has a bypass warning light on the dashboard. This light is deactivated for coldstart since bypass is a normal operation for cold start. With cold oil the machine cannot movewith the bypass open. A temperature sensor is used to communicate the transmission oiltemperature to the monitoring system.

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SBoth machines use a MAC-14, Power Train ECM (1) to control the hydrostatic pumps andmotors. The MAC-14, Power Train ECM is located on the right side of the machine behind theupper enclosure door on the left. The MAC-14 was used on the former 963C, but has beenrotated 90 degrees to provide greater service access. The Power Train ECM system eliminatesthe mechanical linkages associated with the Hydrostatic Power Control Unit (HPCU) whichwas used on the 953/953B and 963/963B.

The Power Train ECM receives input signals from the operator controls: the speed anddirection lever, steering pedals, brake pedal, Work-Travel Mode switch, parking brake switch,or signals from the machine itself (pressures, engine rpm, travel motor speeds, andtemperatures). With this information, the Power Train ECM makes calculations and directsoutput signals to the solenoid valves that control the hydrostatic drive. Speed sensors for theTier II 963C machines are now on the the motors instead of the final drives. The Tier II 953Cmachine sensors are still on the final drives. The sensors are only required for calibrations.

From the engine speed sensor, the Power Train ECM can sense the engine slowing due toincreased load and will automatically upstroke the motors and destroke the pumps to maintainfull power to the implement hydraulics while slowing the tracks, if necessary, to keep enginerpm from going too low.

An additional ECM (2), mounted below the Power Train ECM, is used for the MachineSecurity System. This feature if added to the machine, prevents the engine from starting unlessthe appropriate key is used.

20

STMG 775 - 29 -1/04

1

2

OKTOPU

SThe batteries (1), engine oil fill tube (2), engine oil dip stick (3), fuel pump (4), and airconditioning compressor (5) can be accessed through the right engine compartment at the rearof the machine.

To ensure quick starting down to –18° C (0° F), the machines come standard with a 24-volt, 6 kW (8 hp) capacity starting motor and two 12-volt, 100 amp hour batteries wired in series.The standard battery has 750 amps of cold cranking capacity (CCA).

As an option, the machines can be equipped with two, 172-amp hour, 950 CCA, batteries forstarting the engine down to –32° C (–25° F).

NOTE: This illustration is from a 953C. For the 963C one battery is located on each side ofthe machine.

21

STMG 775 - 30 -1/04

1

24

35

OKTOPU

S22

The primary and secondary air filter elements are located on the left side of the machine in theair cleaner housing (1). The filter element indicator (2) should be checked to determine if theelements require service.

The engine oil filter (3) has been relocated on the 963C to a convenient location just inside anaccess door on the left side of the machine. This makes filter changes easier and decreases therisk of spilling oil when the filter is being changed.

The turbocharger (4) uses exhaust gases to drive the impeller turbine which, in turn, drives anair compressor turbine to pack more air in the cylinders during each intake stroke.

The Power Train ECM manifold (5) is to the left of the air cleaner housing. The functions ofthe Power Train ECM manifold are: control the displacement of the variable pumps andvariable motors, engage or release the parking brakes, control pressure in the charge system,and supply control oil (charge oil) to all the solenoids. The fill tube (6) for the washer reservoirand the cab filter (7) are also located in this compartment.

NOTE: Except for the engine oil filter, component locations are the same on the 953C.

STMG 775 - 31 -1/04

1

2

3

4

5

67

OKTOPU

SA 24 Volt, 70 amp alternator (1) is standard.

The engine coolant tap (2) for S•O•S is located just above the alternator, which is used to takecoolant samples for analysis.

The engine oil filter (3) for the 953C is mounted to the engine block. The engine oil tap (4) forS•O•S is located just above the filter.

The electric starter motor (not shown) and the starter relay are controlled by the Engine ECM.They are not wired directly to the key start switch. The Engine ECM prevents fuel beingsupplied to the engine for starting until sufficient oil pressure is present to prevent bearing weardue to operating without adequate lubrication.

23

STMG 775 - 32 -1/04

1

2

3

4

OKTOPU

SENGINE

The engine in the updated machines is a Cat 3126B, electronically controlled, six-cylinder,design that provides long, effective power strokes for high torque and efficient fuel combustion.The 3126B replaces the 3116 engine. Displacement of the 3126B is 7.2 L (442 in3), 9% morethan the 6.6 L (403 in3), 3116 engine in the former machines.

This engine is equipped with: Hydraulic-actuated Electronic Unit Injectors (HEUI), an air toair aftercooler (ATAAC), three valves per cylinder, and a turbocharger. The engine is controlledand monitored by an Advanced Diesel Engine Management (ADEM III) - Electronic ControlModule, which monitors all major engine functions and regulates the HEUI. These advancedelectronics add value by improving power density through torque shaping, help to reduceemissions, and monitor and control engine systems.

The 3126B in the 953C is rated at 95 net kW (128 net hp) at 2000 rpm, but reaches a maximumof 96 kW (129 net hp) when lugged down into the "working range." The 3126B in the 963C israted at 118 net kW (158 net hp) at 2000 rpm, but reaches a maximum of 119 net kW (159 nethp) when lugged down into the "working range." The engine provides power and acts as aworking counterweight in the rear of the machine for optimum machine balance.

24

STMG 775 - 33 -1/04

OKTOPU

S

Hydraulic-actuated Electronic Unit Injection is a unique and proven high-pressure, directinjection fuel system for diesel engines. The unit injectors combine the injector nozzle andhigh-pressure pump into one assembly for each cylinder, for excellent control of fuel deliveryand injection timing under all loads and speeds. External high-pressure fuel lines areeliminated. This system provides very high injection pressure and short injection duration forfast response, low fuel consumption, and excellent emissions control.

STMG 775 - 34 -1/04

OKTOPU

SThe ADEM III Engine ECM (arrow) for the engine is mounted behind the fuel filter/waterseparator.

The fuel injection system responds to signals from the Engine ECM which electronicallymonitors operator and sensor inputs to provide engine control not possible with a mechanicallyoperated fuel injection. Engine performance is optimized over the entire operating range.

The Engine ECM continuously monitors:

- engine oil pressure- engine oil temperature- intake manifold temperature- coolant temperature- fuel pressure- engine rpm- operator selected rpm

The HEUI system is able to independently control:- injection pressure- duration of the injection impulse- volume of fuel injected- timing of when the fuel is injected

25

STMG 775 - 35 -1/04

OKTOPU

S

Precise control of the fuel injection process permits the HEUI system to control heat releaseduring combustion in the power stroke for:

- increased fuel economy (amount of fuel consumed per unit of power produced per hour)- reduced emission levels- improved torque rise- easier cold starting- reduced combustion noise

STMG 775 - 36 -1/04

OKTOPU

SThe engine speed sensor (2) on the 963C can be seen from the right side of the machinethrough the front service compartment to the right of the ADEM III (1). The speed sensor ismounted in the flywheel housing.

26

STMG 775 - 37 -1/04

1

2

OKTOPU

S27

Cat ET must used to access the machine ECMs.

The ECM Selector Screen shows this particular machine is equipped with five ECMs.

The monitoring system is "flashable" on the updated models.

STMG 775 - 38 -1/04

OKTOPU

S28

When the "3126B 963 TTL" ECM is selected, the technician can gain access to the the engineconfiguration screen.

The technician has limited capabilities to change parameters with this particular engine.

STMG 775 - 39 -1/04

OKTOPU

S29

HYDRAULIC SYSTEMS

The hydraulic portion of 963C power train consists of the following major components:

- two variable displacement, axial piston drive pumps with charge pumps

- two variable displacement, link-type, piston motors

- synchronization manifold

- Power Train ECM manifold

- charge filter

- case drain filter

STMG 775 - 40 -1/04

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The 963C hydraulic implement system consists of:

- a fixed displacement, vane-type pump

- main control valve group

- an optional third control valve with a main relief valve

- pilot valve group

- pressure reducing valve

If no third valve is used, the main relief valve is located in the main control valve group. Thepressure reducing valve is used to provide pilot oil to the pilot valves.

The two systems share a common hydraulic tank.

STMG 775 - 41 -1/04

OKTOPU

S30

The 953C power train and implement hydraulic systems are similar. The 953C power trainsystem has only one charge pump. An accumulator in the charge circuit has been added on theupdated machines to help maintain the needed charge flow and pressure.

The 953C implement control valves are located in the hydraulic tank. An accumulator is usedto assist with lowering implements with a dead engine.

The 953C is equipped with two case drain filters.

The main relief valve is mounted to the implement pump.

STMG 775 - 42 -1/04

Lift

Cylinders

Ripper and

Mult i-purpose

Bucket  Cylinders

Tilt

Cylinder

Implement

Pump

Left  PumpLeft  Motor

Synchronizat ion

Manifold

Main Control

Valve Group

 Attach

Control

Valve

 Tank

Pilot  Valve Group

ECM

Manifold

Right  PumpRight  Motor

953C POWER TRAIN AND IMPLEMENT HYDRAULIC SYSTEMCOMPONENT IDENTIFICATION

OKTOPU

S31

The left (1) and right (2) hystat pumps, the vane-type implement pump (3), and thesynchronization manifold (4) are located below the cab on both models. This illustration isfrom a 953C. Various pressure taps can be accessed with the cab floor plate removed.

The pressure taps on the synchronization manifold are for left pump forward and reverse driveloop and right pump forward and reverse drive loop pressures. The synchronization solenoidvalve (5) is used to connect both pump drive loops for straight travel in either FORWARD orREVERSE.

The splitter box (6) contains the pump drive gears which transfer horsepower from the engineflywheel to the respective pump. The gear ratio to drive the hystat pumps was changed from a1:1 ratio to a 1:1.1 ratio to compensate for the lower maximum full load engine speed. Theengine speed changed from 2200 rpm to 2000 rpm.

The main relief valve (7) is mounted on the top of the implement pump.

The 953C uses a different implement pump than the 963C machines. The pumps, however, arethe same as used on the former 953C and 963C machines.

STMG 775 - 43 -1/04

12

34

5

6

7

OKTOPU

SEach hystat pump has additional pressure taps mounted to them. Shown is the pump on a963C.

- The X1 or forward signal pressure from the pump control valve to the actuator tap (1) isshown above the other taps.

- The X2 or reverse signal pressure from the pump control valve to the actuator tap (2) isshown below the other taps.

- The case drain tap (3) is located between the other two taps.

The pump control valve (4), to the left of the taps, is also mounted to the pump. The pumpcontrol valve directs signal oil to either side of the pump actuator to control stroking of thepump.

32

STMG 775 - 44 -1/04

1

23

4

OKTOPU

S33

The Power Train ECM manifold (1) contains the following components:

- brake solenoid (2)

- left drive loop steering solenoids: forward (3), reverse (4)

- right drive loop steering solenoids: forward (6), reverse (5)

- transmission override solenoid (7)

- override pressure sensor (8)

Not shown are: the left and right resolver, left signal pressure sensor, right signal pressuresensor, and charge relief valve which are also located in or near the Power Train ECMmanifold.

The override pressure sensor sends an analog signal to the converter (16). The converterchanges the analog signal to a digital PWM signal. The PWM signal goes to the Power TrainECM.

STMG 775 - 45 -1/04

1

2

3 4

567

8

9

10

11 12

13

14

15

16

OKTOPU

S

To make problem diagnosis faster and easier, quick-connect pressure fittings are part of thehydrostatic and implement hydraulic systems. Pressure taps shown are:

- charge pressure (9)

- brake control pressure (10)

- left forward signal pressure (11) from the left forward steering solenoid

- right forward signal pressure (12) from the right forward steering solenoid

- left reverse signal pressure (13) from the left reverse steering solenoid

- right reverse signal pressure (14) from the right reverse steering solenoid

The functions of the Power Train ECM manifold are to:

- control the displacement of the variable pumps and variable motors

- engage or release the parking brakes

- control maximum charge pressure in the charge system

- supply control oil (charge oil) to all the solenoids

The remaining tap (15) is for checking the maximum implement supply pressure on a 963C.

STMG 775 - 46 -1/04

OKTOPU

SThe pilot system tap (1) and pilot system accumulator (2) for the 953C are located below thecab on the right side of the machine.

The pilot system accumulator is used to lower the implements with the engine off.

The 963C is not equipped with a pilot accumulator. A resolver in the loader circuit is used toprovide dead engine lowering capabilities.

34

STMG 775 - 47 -1/04

1

2

OKTOPU

SThe tap (1) to check the implement hydraulic system is locate to the left of the Power TrainECM manifold.

The 953C is equipped with an additional accumulator (2), which is used for the hystat hydraulicsystem. The accumulator is used to assist the single charge pump in maintaining charge systemflow and pressure needs.

The accumulator is located on the left side of the machine below the cab.

35

STMG 775 - 48 -1/04

1

2

OKTOPU

SThe 963C motor speed sensor (1) senses how fast the motor is turning and communicates thisto the Power Train ECM. The Power Train ECM will use this information to control the pumpsand motors to control machine tracking. During calibrations the ECM matches the right sidemotor speed to the left side motor speed. The left side motor speed input is fixed at six pointsthrough the software.

The minimum angle stop adjustment screw (2) is used to limit the minimum motordisplacement angle to control the maximum speed.

Screw (3) controls the stroking rate of the motor. The screw is used to set how much signalpressure is required to initiate shifting of the motor actuator.

NOTE: The speed sensor for the 953C is still mounted in the final drive and senses thebullgear teeth as they pass.

36

STMG 775 - 49 -1/04

1

2

3

OKTOPU

SFrom the other side of the 963C drive motor, the flushing valve (1), the pressure override valve(3), and the maximum angle stop screw (2) can be found.

During normal operation, the maximum angle stop screw is used to set the minimum machinespeed.

The pressure override valve, used only on the 963C, senses the drive loop pressure. When thepressure exceeds the valve setting, the valve opens and directs signal oil to the motor actuatorto the tank, which causes the motor to move toward maximum angle, thereby, reducing machinespeed and increasing torque to the drive sprockets.

The flushing relief valve (4) is part of the flushing valve. When the machine is moving, theflushing relief valves maintain a minimum pressure in the low pressure side drive loop andcharge circuit (internal drive loop leakage must not exceed flow output of charge pump).

37

STMG 775 - 50 -1/04

1

2

3

4

OKTOPU

S38

963C Power Train Hystat Hydraulic System

The left drive pump and drive motor make up the left drive loop. The right drive loop consistsof the right drive pump and drive motor. When the machine is not turning, the synchronizationvalve ensures that the drive pressures are equal in the left and right drive loops to allow forstraight travel. The power train ECM will de-energize the valve in underspeed conditions.

The left drive pump contains makeup and line relief valves, a pump control valve, an actuator,and a charge pump.

The charge pumps supply oil to the drive loops and the Power Train ECM manifold. Thecharge pumps provide oil for the following functions: steering valve operation, pump actuatordisplacement, parking brake operation, and flushing and cooling flow for the drive pumps andmotors. The charge pumps also supply the pilot oil to the implement hydraulic system.

The line reliefs control the maximum drive loop pressures, while the makeup valves allowcharge oil to replenish the low pressure drive loops.

STMG 775 - 51 -1/04

MotorControlValve

DriveMotorGroup

ActuatorPiston

Left DriveMotor Group

Left PumpControlValve

Left PumpActuator

FlushingShuttleValve

FlushingRelief Valve

SynchronizationValve

ParkingBrake

SynchronizationManifold

PressureOverride

Valve

963C POWER TRAIN HYDRAULIC SYSTEMLEFT DRIVE LOOP

Left DrivePump Group

ChargePump

PressureReducing

Valve

ChargeFilter

OKTOPU

S

The pump control valve directs oil from the charge pump to shift the pump actuator. The pumpactuator strokes the pump to increase flow for machine movement.

The left drive motor contains the flushing shuttle valve, flushing relief valve, actuator piston,motor control valve, pressure reducing valve, and a pressure override valve.

The flushing shuttle valve allows a continuous flow of oil from the low pressure side of thedrive loop to enter the motor case when the machine is moving. This purge flow removescontaminants that enter the drive loops or the contaminants that are created within the driveloops. The purge flow also removes hot oil that can be generated in the drive loop. When themachine is moving, the flushing relief valves maintain a minimum pressure in the low pressureside drive loop and charge circuit (internal drive loop leakage must not exceed flow output ofcharge pump).

The motor actuator piston is controlled by the motor control valve and pressure override valve.The signal oil from the steering solenoid valves is directed to the motor control valve to causethe motor to destroke for faster machine speed. The pressure override valve will destroke themotor hydraulically when its setting is overcome.

The pressure reducing valve is used to prevent pressure spikes to the motor actuator.

The right drive loop features similar components except for not having the synchronizationmanifold and solenoid valve mounted to it.

The two drive loops share a common charge filter.

The synchronization manifold is used to keep the left and the right drive pressures equal whenthe machine is not turning. When the machine is traveling in straight line, the Power TrainECM will energize the synchronization valve to connect the left and right drive loops.

When the drive loops are connected the flow and the pressure between the two drive loopsequalize to provide straight travel.

The synchronization valve is energized by the Power Train ECM without any input from theoperator. The synchronization valve is de-energized when a steering pedal is depressed orwhen underspeed conditions occur. De-energizing the synchronization valve blocks flowbetween the left and right drive loops.

NOTE: The update 963C power train hydraulic system is very similar to the previous 963Csystem. Some of the line routings have changed. These changes are shown throughout thefollowing 963C power train schematics.

STMG 775 - 52 -1/04

OKTOPU

S39

The Power Train ECM manifold receives electrical signals from the Power Train ECM.Electrical signals are used to control the following solenoid valves:

- parking brake control valve

- transmission override valve

- left forward steering valve

- left reverse steering valve

- right forward steering valve

- right reverse steering valve

The Power Train ECM uses the transmission override solenoid valve to put the machine inNEUTRAL if certain electrical faults exist. The proportional solenoid valve is used as anon/off valve. When the solenoid is de-energized the flow of oil is blocked. This causes thepumps to destroke to NEUTRAL.

STMG 775 - 53 -1/04

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OKTOPU

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The parking brake solenoid valve engages the brakes. The brakes are spring applied andhydraulically released. When the operator places the speed/direction control lever in the PARKposition, the Power Train ECM de-energizes the parking brake solenoid valve which relievesthe hydraulic pressure and the brakes are engaged. When the machine is NOT in the PARKposition, the Power Train ECM energizes the solenoid valve which directs the charge pressureoil to the brakes to release the brakes. The Power Train ECM uses a +battery signal to activatethe parking brake solenoid.

The parking brake switch on the console or the center foot pedal can also de-energize theparking brake solenoid valve to engage the brakes.

The four steering solenoid valves and the transmission override solenoid valve are proportional.The Power Train ECM uses the proportional steering solenoid valves to control the speed andthe direction of the machine. The Power Train ECM directs a pulse width modulated (PWM)signal to the appropriate steering solenoid valves. This PWM signal is based on theinformation from the following:

- speed/direction control lever- left pedal- right pedal- center pedal

The PWM signal varies the hydraulic signal output of the solenoid valve. The amount of signaloil controls the swashplate angle of the pumps and motors.

The following sensors provide feedback to the Power Train ECM:

- override pressure sensor- pressure sensor for the signal to the right drive motor- pressure sensor for the signal to the left drive motor

The PWM sensors for the signal pressure to the motors direct input signals to the Power TrainECM that indicate the output pressure of the steering valves. The Power Train ECM uses thisinput in order to determine if a steering valve is sticking.

The override pressure sensor senses the charge system pressure and sends an analog signal to aconverter. The converter changes the analog signal to a PWM signal which is sent to the PowerTrain ECM. The Power Train ECM uses the information for the override pressure in order todetermine if the brake pressure and the lubrication pressure are correct. If the pressure is notcorrect and the machine is not in PARK, the Power Train ECM will inform the operator byturning on a monitoring system alert indicator.

The right signal resolver and the left signal resolver sense the FORWARD and REVERSEsignal pressures from the steering valves. The signal resolvers send the higher pressure to therespective drive motors. These signal pressures are sent to the motor control valves in order tocontrol the output of the drive motors. The charge relief valve limits the pressure that is sentfrom the charge pumps.

STMG 775 - 54 -1/04

OKTOPU

S40

The test ports shown above are used when testing the 963C hystat hydraulic system.

The "M" port is used to check the pressure to the motor actuator.

STMG 775 - 55 -1/04

ChargePressure

LeftForward

RightReverse

RightForward

LeftReverse

Charge Pressure

Reverse SignalPressure

Forward SignalPressure

Parking BrakePressure

Reverse SignalPressure

"M" Port

"M" Port Forward ActuatorPressure

Reverse ActuatorPressure

963C POWER TRAIN HYDRAULIC SYSTEMPRESSURE FITTING LOCATIONS

OKTOPU

S41

When the engine is started with the speed/direction control lever in PARK, the charge pumpsdraw tank oil from the hydraulic tank (not shown). The charge pumps direct the chargepressure oil to the charge filter. A bypass valve inside the housing opens if the pressuredifferential becomes too high. Cold charge oil that has bypassed the charge filter is directed toa check valve by the bypass valve.

This check valve helps the charge system maintain adequate lubrication pressure until thesystem oil is warm enough to flow through the charge filter. If the pressure differential acrossthe filter exceeds the specification, the oil flow from the charge pumps is also directed to thehydraulic tank.

The monitoring system provides input into the Power Train ECM as to the status of the bypassswitch. With cold oil the machine cannot move with the bypass open. A temperature sensor isused to communicate the transmission oil temperature to the monitoring system.

As the oil temperature increases to normal operating temperatures, the filter bypass valvecloses. Now if the bypass valve opens the monitoring system will signal the Power Train ECMthe open status of the bypass valve. The Power Train ECM will stop the machine.

STMG 775 - 56 -1/04

963C POWER TRAIN HYDRAULIC SYSTEMPARK

FlushingValve

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

ChargeReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Case DrainFilter

Actuator

Pump Control Valve

MotorControl Valve

OKTOPU

S

After the charge oil flows through the charge filter, the oil is directed to four areas:

- the low pressure side of both drive loops through makeup and line relief valves and thepump control valves in the drive pumps

- charge relief valve on the Power Train ECM manifold

- transmission override valve and brake control valve

- the implement circuit to provide pilot oil

The drive loops constantly lose oil through leakage in the drive pumps and in the drive motors.Also, the drive loops lose oil through the flushing valves when the machine is moving. Thesupply of charge pressure oil replenishes the low pressure sides of both drive loops through themakeup and line relief valves. The flushing oil directs contaminants and hot oil out of the drivepumps and drive motors to the case drain filter.

The override pressure sensor provides information on the override pressure to the Power TrainECM. If the override pressure drops below the level that is required in order to keep the brakesfrom engaging during travel, a warning is issued to the Caterpillar Monitoring System if themachine is traveling.

The synchronization valve is energized when the speed/direction control lever is in the PARKposition. Energizing the synchronization valve allows the left drive loop and the right driveloop to be connected in order to equalize the flow and the pressure between the two drive loopsto provide straight travel.

The drive pumps are at zero swashplate angle and the port plates in the drive motors are at themaximum angle when the speed/direction control lever is in the PARK position.

When the speed/direction control lever is in the PARK position, the flushing valves are in thecenter position, blocking oil in the drive loops from flowing to the flushing relief valves. Anorifice in each pump allows some flushing of the charge oil.

When the speed/direction control lever is in the PARK position, the transmission override valveis DE-ENERGIZED by the power train ECM in order to put the machine in NEUTRAL, whichblocks charge oil to the steering valves.

When the speed/direction control lever is in the PARK position, the steering valves are also inthe DE-ENERGIZED position. In this position, the steering valves drain oil from both ends ofpump control valves in the drive pumps. The pump control valve moves to the center positionto drain oil from both sides of the pump actuator. Springs in the pump actuator move the pumpswashplate to zero angle.

Also, the steering valves drain oil from motor control valves in the drive motors to keep theport plates in the drive motors at maximum angle.

STMG 775 - 57 -1/04

OKTOPU

S42

When the brakes are disengaged, the Power Train ECM processes the information from thesensor on the speed/direction control lever. The Power Train ECM sends a signal to the brakecontrol valve. When the brake control valve is energized, charge oil is directed to the brakes torelease the brakes.

STMG 775 - 58 -1/04

963C POWER TRAIN HYDRAULIC SYSTEMBRAKES RELEASED

FlushingValve

Pump Control Valve

Actuator

Pressure OverrideValve

MotorControl Valve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

ChargeReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Case DrainFilter

Actuator

OKTOPU

S43

When the operator shifts the speed/direction control lever to the maximum FORWARDposition, the Power Train ECM processes the information from the sensor on thespeed/direction control lever. The Power Train ECM sends an electrical signal to thetransmission override valve. The ECM also directs PWM signals to the steering valves. Theenergized transmission override valve supplies charge oil to the steering valves.

As the steering valves are energized, each valve directs signal oil to the drive pumps. Thesignal oil to the drive pumps causes the swashplates to move. When the signal pressureincreases, the pump control valves shift. When the pump control valves shift, charge oil isdirected to one side of the pump actuator. The actuator shifts and moves the pump swashplate.Pump flow increases.

The signal oil is also directed to drive motors through the signal resolvers. When the pressureincreases enough to shift the motor control valves, drive loop oil is directed to the motoractuators and pressure override valves. The actuators shift and move the port plates towardminimum angle.

STMG 775 - 59 -1/04

963C POWER TRAIN HYDRAULIC SYSTEMMAXIMUM FORWARD

FlushingValve

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

ChargeReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Case DrainFilter

Actuator

Pump Control Valve

MotorControl Valve

OKTOPU

S

The pressure in the FORWARD drive loop is proportional to the drawbar pull. The pressure islimited by the line relief function of the makeup and line relief valves.

When the speed/direction control lever is in the maximum FORWARD position, the PowerTrain ECM sends PWM signals to the right forward steering valve and left forward steeringvalve.

The steering valves direct signal oil to the drive pumps in order to stroke the pumps. Also, thesteering valves direct signal oil to the drive motors in order to destroke the motors. Theswashplates in the drive pumps rotate and the pump flow pressurizes the FORWARD side ofthe drive loops.

The motor flushing shuttle valves shift to direct charge oil into an orifice and to the flushingrelief valves. When the machine is moving, the flushing relief valves maintain a minimumpressure in the low pressure side drive loop and charge circuit (internal leakage must notexceed flow output of charge pump). Maintaining the charge pressure is required to fullyrelease the brakes and to fully shift the pumps and motors.

To maintain the correct tracking of the machine, the Power Train ECM energizes thesynchronization valve. This connects the left and the right drive loops in order to providestraight travel. The synchronization valve is opened in the FORWARD and REVERSEdirections.

To reach full FORWARD, the signal oil from the steering valves moves the actuators in thedrive pumps. The drive pumps will upstroke to the maximum swashplate angle. This generatesapproximately 33% of the maximum machine speed. The drive motors receive the same signaloil from the steering valves. The motors will begin to destroke once the maximum swashplateangle is reached in the respective drive pumps. Machine speed will continue to increase untilthe machine reaches the maximum speed of approximately 9.5 km/h (5.9 mph).

The underspeed feature is automatically utilized when the load on the drawbar causes theengine to lug. The underspeed feature overrides the input of the speed/direction control lever.The underspeed feature will change the speed setting of the machine in order to keep the enginespeed at the designated rpm by reducing the current to the steering valves, which reduces thesignal pressure to the drive pumps and motors. The drive motors will upstroke first and thendrive pumps will destroke. The engine speed is maintained regardless of the changing loads.There is no adjustment for the designated engine speed under load.

This engine speed is determined by the programmed software in the Power Train ECM. Theimplement circuit has priority over the transmission to use engine horsepower. When theengine lugs, the Power Train ECM uses the underspeed feature to reduce speed of the tracks byreducing the electrical signal to the steering valves. This will reduce the load on the engine.When the engine has returned to normal operating speed, the full electrical signal will return tothe steering valves.

STMG 775 - 60 -1/04

OKTOPU

S

When the engine lugs heavily due to high loads, the synchronization valve is de-energized bythe Power Train ECM. The valve closes and blocks the flow between the drive loops in orderto prevent the engine from stalling. The ECM monitors the loading of the engine with themagnetic engine speed sensor that is mounted on the engine flywheel housing. The magneticengine speed sensor generates a signal that varies in proportion to the engine speed.

When drive loop pressure exceeds the motor pressure override valve spring setting due to highloads, the valve shifts and drains oil to the large end of actuator to the tank. Pressure workingon the other end of the actuator will cause the actuator to shift to upstroke the motor.

STMG 775 - 61 -1/04

OKTOPU

S44

To make a right turn when the machine is traveling in FORWARD, the right steering pedal ispartially depressed which causes the synchronization valve to be de-energized.

The synchronization valve is DE-ENERGIZED at the initial depression of the steering pedal inorder to separate the drive loops. If the valve is not DE-ENERGIZED at the initial depressionof the steering pedal, small steering turns at the initial depression of the steering pedal are notpossible.

As the steering pedal is depressed, the PWM signal from the rotary sensor on the pedal isdirected to the Power Train ECM. The Power Train ECM sends a reduced PWM signal to rightFORWARD steering valve. The right FORWARD steering valve reduces the signal oil to theright drive pump control valve and to the right drive motor control valve. The control valvesshift according to the amount of signal reduction. The motor control shifts first.

STMG 775 - 62 -1/04

FlushingValve

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

ChargeReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Case DrainFilter

Actuator

963C POWER TRAIN HYDRAULIC SYSTEMRIGHT TURN FORWARD

Pump Control Valve

MotorControl Valve

OKTOPU

S

As the motor control valve shifts, pressure on the head end of the actuator is reduced. Theactuator starts to move to the left which increases the angle of the port plate in the drive motoras the operator depresses the right steering pedal. When the right steering pedal is depressedenough in order to slow the right track to 33% of the maximum speed, the angle of the portplate in the right drive motor reaches the maximum angle.

Then, as the right steering pedal is depressed further, the pump control valve moves to reducepressure at the pump actuator. The swashplate for the right drive pump starts to move towardzero angle.

Due to the left drive pump being upstroked and the motor being destroked, the left trackmaintains speed,while the right track slows down . The machine makes a right turn.

Operation for a left turn is similar for the left drive loop.

NOTE: If the initial steering response occurs at a position besides the initial depression of thesteering pedal, the steering pedal may need to be calibrated.

STMG 775 - 63 -1/04

OKTOPU

S45

If the operator depresses the right steering pedal completely, the Power Train ECM will stop thePWM signal to the right forward steering valve. Then, the Power Train ECM sends a PWMsignal to the right reverse steering valve. The right reverse steering valve directs signal oil tothe right drive pump and drive motor. The signal oil shifts the pump control valve, whichdirects charge oil to the other side of the pump actuator. The swashplates shifts overcenter todirect oil flow to the REVERSE side of the drive loop.

The right drive motor rotates in the REVERSE direction while the left drive motor continues torotate in the FORWARD direction. The synchronization valve is DE-ENERGIZED at the initialdepression of the steering pedal in order to separate the drive loops. If the valve is not DE-ENERGIZED at the initial depression of the steering pedal, steering turns are erratic.

NOTE: If the initial steering response occurs at a position besides the initial depression of thesteering pedal, the steering pedal may need to be calibrated.

STMG 775 - 64 -1/04

963C POWER TRAIN HYDRAULIC SYSTEMRIGHT SPOT TURN

FlushingValve

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

ChargeReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Case DrainFilter

Actuator

Pump Control Valve

MotorControl Valve

OKTOPU

S46

When the operator partially depresses the center pedal, the Power Train ECM reduces the PWMsignal to the energized steering valves to reduce signal oil to the control valves on the pumpand motors. The motor control valve shifts first to drain oil to the motor actuator to the tank.The pump control valve then shifts to drain oil to the pump actuator to the tank.

At maximum speed, partial depression of the center pedal will cause the motor control valves toshift the motor actuators causing the port plates in the drive motors to move toward themaximum angle. When the center pedal is depressed enough in order to lower the machinespeed to 33% of maximum speed, the port plates in the drive motors reach the maximum angle.Further depression of the center pedal will move the pump control valves to shift the pumpactuators to move the pump swashplates toward the minimum angle.

The machine starts to slow down. The further the center pedal is depressed, the more themachine slows down.

STMG 775 - 65 -1/04

963C POWER TRAIN HYDRAULIC SYSTEMCENTER PEDAL PARTIAL DEPRESSED

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

ValveREV

FWD

Motor

Case DrainFilter

Actuator

Pump Control Valve

MotorControl Valve

OKTOPU

S47

When the operator fully depresses the center pedal while moving in a direction, the Power TrainECM minimizes the PWM signal to the energized steering valves to reduce the signal oil to thethe pumps and the motors.

When the center pedal is fully depressed, the motor control valves shift to drain oil to the motoractuators. The actuators shift and move the port plates in drive motors to the maximum angle.Due to the loss of signal oil, the pump control valves and actuators shift to move theswashplates toward the minimum angle. The pumps stay slightly stroked to maintain pressurein the respective drive loop. The machine abruptly stops because of the dynamic braking of thepower train hydraulic system. The brake valve is also DE-ENERGIZED blocking charge oil tothe parking brakes. The parking brakes engage and the motors stop.

There may be a slight growling from the power train hydraulic system when the brakes are fullyapplied. The flow from the drive pumps is the source of the growling. The center pedal shouldbe depressed when the operator is working on a slope in order to prevent the machine fromrolling down the slope. While the center pedal is depressed, the operator may move thespeed/direction control lever in order to demand travel. When the operator slowly releases thecenter pedal, the operator has precise control of the machine.

STMG 775 - 66 -1/04

Actuator

Pressure OverrideValve

Brake

Synchronizat ion Valve

RightSteeringValves

LeftSteeringValves

FWD

REV

BrakeControlValve

TransmissionOverride

Valve

REV

FWD

Motor

Case DrainFilter

Actuator

963C POWER TRAIN HYDRAULIC SYSTEMCENTER PEDAL FULLY DEPRESSED

Pump Control Valve

MotorControl Valve

OKTOPU

S48

953C Power Train Hystat Hydraulic System

The left drive pump and drive motor make up the left drive loop. The right drive loop consistsof the right drive pump and drive motor. When the machine is not turning, the synchronizationvalve ensures that the drive pressures are equal in the left drive loop and in the right drive loop.

The left drive pump contains makeup and line relief valves, a pilot spool, a pump control valve,an actuator, and a charge pump.

The charge pump supplies oil to the drive loops and the Power Train ECM manifold. Thecharge oil provides oil for the following functions: steering valve operation, pump and motordisplacements, parking brake operation, and flushing and cooling flow for the drive pumps andmotors. The charge pumps also supply the pilot oil to the implement hydraulic system.

The line reliefs control the maximum drive loop pressures while the makeup valves allowcharge oil to replenish the low pressure drive loops.

STMG 775 - 67 -1/04

SynchronizationManifold

SynchronizationValve

ChargePump

ChargeFilter

PilotSpool

Pump ControlValve

ControlPiston

Makeup andLine Relief Valves

ParkingBrakes

Left DriveMotor

DrivePump

FlushingShuttleValve

ActuatorPiston

FlushingReliefValve

Motor ControlValve

953C POWER TRAIN HYDRAULIC SYSTEM LEFT DRIVE LOOP / ENGINE OFF

OKTOPU

S

The pilot spool shifts the pump control valve to direct charge pressure oil to shift the pumpactuator. The pump actuator strokes the pump to increase flow for machine movement.

The left drive motor contains the flushing shuttle valve, flushing relief valve, actuator piston,and motor control valve. A pressure override valve is not used on the 953C motors.

The flushing shuttle valve allows a continuous flow of oil from the low pressure side of thedrive loop to enter the motor case when the machine is moving. This purge flow removescontaminants that enter the drive loops or the contaminants that are created within the driveloops. The purge flow also removes hot oil that can be generated in the drive loop. When themachine is moving, the flushing relief valves maintain a minimum pressure in the low pressureside drive loop and charge circuit (internal leakage must not exceed flow output of chargepump). Maintaining the charge pressure is required to fully release the brakes and to fully shiftthe pumps and motors.

The motor actuator piston is controlled by the motor control valve. The signal oil from thesteering solenoid valves is directed to the control valve to cause the motor to destroke for fastermachine speed.

The right drive loop features similar components except for not having the synchronizationmanifold mounted to it and no charge pump.

The two drive loops share a common charge filter.

The synchronization manifold is used in order to keep the left drive pressure and the right drivepressure equal when the machine is not turning. When the machine is traveling in straight linethe Power Train ECM will energize the synchronization valve to connect the left drive loop andthe right drive loop.

When the drive loops are connected the flow and the pressure between the two drive loopsequalize. This provides straight travel.

The synchronization valve is energized by the Power Train ECM without any input from theoperator. The synchronization valve is de-energized when a steering pedal is depressed orwhen underspeed conditions occur. De-energizing the synchronization valve blocks flowbetween the left drive loop and the right drive loop.

NOTE: The updated 953C power train hydraulic system is very similar to the previous 953Csystem. Some of the line routings have changed along with the addition of a accumulator inthe charge circuit. These changes are shown throughout the following 963C power trainschematics.

STMG 775 - 68 -1/04

OKTOPU

S49

The test ports shown above are used when testing the 953C hystat hydraulic system.

STMG 775 - 69 -1/04

BrakePressure

ForwardSignal

Pressure

ReverseSignal

Pressure

Left ReverseDrive Pressure

Left ForwardDrive Pressure

Right ReverseDrive Pressure

Right ForwardDrive Pressure

ChargePressure

DestrokeActuatorPressure

Reverse

Forward

UpstrokeActuatorPressure

UpstrokeActuatorPressure

CaseDrain

Case Drain

953C POWER TRAIN HYDRAULIC SYSTEMPRESSURE FITTING LOCATIONS

OKTOPU

S50

When the engine is started with the speed/direction control lever in PARK, the charge pumpdraws tank oil from the hydraulic tank (not shown). The charge pumps direct the chargepressure oil to the charge filter. A bypass valve inside the housing opens if the pressuredifferential becomes too high. Cold charge oil that has bypassed the charge filter is directed toa check valve by the bypass valve.

This check valve helps the charge system maintain adequate lubrication pressure until thesystem oil is warm enough to flow through charge filter. If the pressure differential across thefilter exceeds the specification, the oil flow from the charge pump is also directed to thehydraulic tank.

The monitoring system provides input into the Power Train ECM as to the status of the bypassswitch. With cold oil the machine cannot move with the bypass open. A temperature sensor isused to communicate the transmission oil temperature to the monitoring system.

As the oil temperature increases to normal operating temperatures, the filter bypass valvecloses. Now if the bypass valve opens the monitoring system will signal the Power Train ECMthe open status of the bypass valve. The Power Train ECM will stop the machine.

STMG 775 - 70 -1/04

Case Drain Filters

LeftDriveLoop

RightDriveLoop

Accumulator

FlushingValve

Actuator

Brake

SynchronizationValve

RightSteeringValves

Left SteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

Charge ReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Actuator

REV

PilotSpool

DriveMotor

953C POWER TRAIN HYDRAULIC SYSTEMPARK

MotorControl Valve

PumpControlValve

OKTOPU

S

After the charge oil flows through the filter, the oil is directed to five areas:

- the low pressure side of both drive loops through makeup and line relief valves and thepump control valves in the drive pumps

- the accumulator and charge relief valve on the Power Train ECM manifold

- transmission override valve and brake control valve

- the implement circuit to provide pilot oil

- the travel motor control valves

The accumulator stores and provides a supply of oil to maintain the charge system flow andpressure.

The drive loops constantly lose oil through leakage in the drive pumps and in the drive motors.Also, the drive loops lose oil through the flushing valves when the machine is moving. Thesupply of charge pressure oil replenishes the low pressure sides of both drive loops through themakeup and line relief valves. The flushing oil directs contaminants and hot oil out of the drivepumps and drive motors to the case drain filter.

The override pressure sensor provides information on the override pressure to the Power TrainECM. If the override pressure drops below the level that is required in order to keep the brakesfrom engaging during travel, a warning is issued to the Caterpillar Monitoring System.

The synchronization valve is energized when the speed/direction control lever is in the PARKposition. Energizing the synchronization valve allows the left drive loop and the right driveloop to be connected in order to equalize the flow and the pressure between the two drive loopsto provide straight travel.

The drive pumps are at zero swashplate angle and the port plates in the drive motors are at themaximum angle when the speed/direction control lever is in the PARK position. When thespeed/direction control lever is in the PARK position, the flushing valves are in the centerposition blocking drive loop oil from the flushing relief valves.

When the speed/direction control lever is in the PARK position, the transmission override valveis DE-ENERGIZED by the power train ECM in order to put the machine in NEUTRAL. The DE-ENERGIZED position blocks oil from the charge pump to the steering valves.

When the speed/direction control lever is in the PARK position, the steering valves are also inthe DE-ENERGIZED position. In this position, the steering valves drain oil from both ends ofpilot valves in the drive pumps. The pump control valve moves to the center position to drainoil from both sides of the pump actuator. Springs in the pump actuator move the pumpswashplate to zero angle. Also, the steering valves drain oil from control valves in the drivemotors to keep the port plates in the drive motors at maximum angle.

STMG 775 - 71 -1/04

OKTOPU

S51

When the brakes are disengaged, the Power Train ECM processes the information from thesensor on the speed/direction control lever. The Power Train ECM sends a signal to the brakecontrol valve. When the brake control valve is energized, charge oil is directed to the brakes torelease the brakes.

STMG 775 - 72 -1/04

Case Drain Filters

LeftDriveLoop

RightDriveLoop

Accumulator

FlushingValve

Actuator

Brake

RightSteeringValves

Left SteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

Charge ReliefValve

REV

FWD

ChargeFilter

ChargePump

Motor

Actuator

REV

PilotSpool

DriveMotor

SynchronizationValve

953C POWER TRAIN HYDRAULIC SYSTEMBRAKES RELEASED

MotorControl Valve

PumpControlValve

OKTOPU

S52

When the operator shifts the speed/direction control lever to the maximum FORWARDposition, the Power Train ECM processes the information from the sensor on thespeed/direction control lever. The Power Train ECM sends an electrical signal to thetransmission override valve. The ECM also directs PWM signals to the steering valves. Theenergized transmission override valve supplies charge oil to the steering valves.

As the steering valves are energized, each valve directs signal oil to the drive pumps. Thesignal oil to the drive pumps causes the swashplates to move. When the signal pressureincreases enough, the pilot spools move to shift the pump control valves. When the pumpcontrol valves shift, charge oil is directed to one side of the pump actuator. The actuator shiftsand moves the pump swashplate. Pump flow increases.

The signal oil is also directed to drive motors through the signal resolvers. When the pressureincreases enough to shift the motor control valves, charge oil is directed to the motor actuators.The actuators shift and move the port plates toward minimum angle.

STMG 775 - 73 -1/04

LeftDriveLoop

RightDriveLoop

FlushingValve

Actuator

Brake

RightSteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

Charge ReliefValve

REV

FWD

Motor

Actuator

REV

PilotSpool

DriveMotor

SynchronizationValve

LeftSteeringValves

953C POWER TRAIN HYDRAULIC SYSTEMMAXIMUM FORWARD

MotorControl Valve

PumpControlValve

OKTOPU

S

The pressure in the FORWARD drive loop is proportional to the drawbar pull. The pressure islimited by line relief function of the makeup and line relief valves.

When the speed/direction control lever is in the maximum FORWARD position, the PowerTrain ECM sends PWM signals to the right forward steering valve and left forward steeringvalve.

The steering valves direct signal oil to the drive pumps in order to stroke the pumps. Also, thesteering valves direct signal oil to the drive motors in order to destroke the motors. Theswashplates in the drive pumps rotate and the pump flow pressurizes the FORWARD side ofthe drive loops.

The motor flushing shuttle valves shift to direct charge oil into an orifice and to the flushingrelief valves. When the machine is moving, the flushing relief valves maintain a minimumpressure in the low pressure side drive loop and charge circuit (internal drive loop leakage mustnot exceed flow output of charge pump). The flushing relief valves maintain back pressureagainst the orifices before the oil flows to case drain.

To maintain the correct tracking of the machine, the Power Train ECM energizes thesynchronization valve. This connects the left and the right drive loops in order to providestraight travel. The synchronization valve is opened in the FORWARD direction and in theREVERSE directions.

To reach full FORWARD, the signal oil from the steering valves moves the actuators in thedrive pumps. The drive pumps will upstroke to the maximum swashplate angle to generateapproximately 33% of the maximum machine speed. The drive motors receive the same signaloil from the steering valves. The motors will begin to destroke once the maximum swashplateangle is reached in the respective drive pumps. Machine speed will continue to increase untilthe machine reaches the maximum speed of approximately 9.7 km/h (6.0 mph).

The underspeed feature is automatically utilized when the load on the drawbar causes theengine to lug. The underspeed feature overrides the input of the speed/direction control lever.The underspeed feature will change the speed setting of the machine in order to keep the enginespeed at the designated rpm by reducing the current to the steering valves, which reduces thesignal pressure to the drive pumps and motors. The drive motors will upstroke first and thenthe drive pumps will destroke. The engine speed is maintained regardless of the changingloads. There is no adjustment for the designated engine speed under load.

This engine speed is determined by the programmed software in the Power Train ECM. Theimplement circuit has priority over the transmission to using engine horsepower. When theengine lugs, the Power Train ECM uses the underspeed feature to reduce speed of the tracks byreducing the electrical signal to the steering valves. This will reduce the load on the engine.When the engine has returned to normal operating speed, the full electrical signal will return tothe steering valves.

STMG 775 - 74 -1/04

OKTOPU

S

When the engine lugs heavily due to high loads, the synchronization valve is DE-ENERGIZEDby the Power Train ECM. The valve closes and blocks the flow between the drive loops inorder to maintain engine power. The ECM monitors the loading of the engine with themagnetic engine speed sensor that is mounted on the engine flywheel housing. The magneticengine speed sensor generates a signal that varies in proportion to the engine speed.

STMG 775 - 75 -1/04

OKTOPU

S53

To make a right turn when the machine is traveling in FORWARD, the right steering pedal ispartially depressed which causes the synchronization valve to be de-energized.

The synchronization valve is DE-ENERGIZED at the initial depression of the steering pedal inorder to separate the drive loops. If the valve is not DE-ENERGIZED at the initial depressionof the steering pedal, small steering turns at the initial depression of the steering pedal are notpossible.

As the motor control valve shifts, pressure on the one end of the actuator is reduced. Theactuator starts to move to increase the angle of the port plate in the drive motor as the operatordepresses the right steering pedal. When the right steering pedal is depressed enough in orderto slow the right track to 33% of the maximum speed, the angle of the port plate in the rightdrive motor reaches the maximum angle.

Then, as the right steering pedal is depressed further, the pump pilot spool and pump controlvalve moves to reduce pressure at the pump actuator. The swashplate for the right drive pumpstarts to move toward zero angle.

STMG 775 - 76 -1/04

LeftDriveLoop

RightDriveLoop

FlushingValve

Actuator

Brake

RightSteeringValves

LeftSteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

REV

FWD

Motor

Actuator

REV

PilotSpool

DriveMotor

953C POWER TRAIN HYDRAULIC SYSTEMRIGHT TURN FORWARD

MotorControl Valve

PumpControlValve

OKTOPU

S

Due to the left drive pump being upstroked and the left motor being destroked, the left trackmaintains speed, while the right track slows down . The machine makes a right turn.

Operation for a left turn is similar for the left drive loop.

NOTE: If the initial steering response occurs at a position beside the initial depression of thesteering pedal, the steering pedal may need to be calibrated.

STMG 775 - 77 -1/04

OKTOPU

S54

If the operator depresses the right steering pedal completely, the Power Train ECM will stop thePWM signal to the right forward steering valve. Then, the Power Train ECM sends a PWMsignal to the right reverse steering valve. The right reverse steering valve directs signal oil tothe right drive pump and drive motor. The signal oil shifts the pilot valve, which moves thepump control valve and directs charge oil to the other side of the pump actuator. Theswashplates shifts overcenter to direct oil flow to the REVERSE side of the drive loop.

The right drive motor rotates in the REVERSE direction while the left drive motor continues torotate in the FORWARD direction. The synchronization valve is DE-ENERGIZED at the initialdepression of the steering pedal in order to separate the drive loops. If the valve is not DE-ENERGIZED at the initial depression of the steering pedal, steering turns are erratic.

NOTE: If the initial steering response occurs at a position beside the initial depression of thesteering pedal, the steering pedal may need to be calibrated.

STMG 775 - 78 -1/04

Forward

Reverse

LeftDriveLoop

RightDriveLoop

FlushingValve

Actuator

Brake

RightSteeringValves

LeftSteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

REV

FWD

Motor

Actuator

REV

PilotSpool

DriveMotor

953C POWER TRAIN HYDRAULIC SYSTEMRIGHT SPOT TURN

MotorControl Valve

PumpControlValve

OKTOPU

S55

When the operator partially depresses the center pedal, the Power Train ECM reduces the PWMsignal to the energized steering valves to reduce signal oil to the pilot spool on the pump andthe control valve on the motors. The pilot spool on the pump shifts the pump control valve.When the control valves shift, charge oil is directed to the pump and the motor actuators tocause them to shift. The motor control valve shifts first.

At maximum speed, partial depression of the center pedal will cause the motor control valves toshift the motor actuators causing the port plates in the drive motors to move toward themaximum angle. When the center pedal is depressed enough in order to lower the machinespeed to 33% of maximum speed, the port plates in the drive motors reach the maximum angle.Further depression of the center pedal will move the pump pilot valves and pump control valvesto shift the pump actuators to move the pump swashplates toward the minimum angle.

The machine starts to slow down. The further the center pedal is depressed, the more themachine slows down.

STMG 775 - 79 -1/04

LeftDriveLoop

RightDriveLoop

FlushingValve

Actuator

MotorControl Valve

Brake

RightSteeringValves

LeftSteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

Charge ReliefValve

REV

FWD

Motor

Actuator

REV

PilotSpool

PumpControlValve

DriveMotor

953C POWER TRAIN HYDRAULIC SYSTEMCENTER PEDAL PARTIALLY DEPRESSED

OKTOPU

S56

When the operator fully depresses the center pedal while moving in a direction, the Power TrainECM minimizes the PWM signal to the energized steering valves to reduce the signal oil to thethe pumps and the motors.

When the center pedal is fully depressed, the motor control valves shift to drain oil to the motoractuators. The actuators shift and move the port plates in drive motors to the maximum angle.Due to the loss of signal oil, the pilot spools, pump control valves, and actuators shift to movethe swashplates toward the minimum angle. The machine abruptly stops because of thedynamic braking of the power train hydraulic system. The pumps stay slightly stroked tomaintain pressure in the respective drive loop. The brake valve is also DE-ENERGIZEDblocking charge oil to the parking brakes. The parking brakes engage and the motors stop.

There may be a slight growling from the power train hydraulic system when the brakes are fullyapplied. The flow from the drive pumps is the source of the growling. The center pedal shouldbe depressed when the operator is working on a slope in order to prevent the machine fromrolling down the slope. While the center pedal is depressed, the operator may move thespeed/direction control lever in order to demand travel. When the operator slowly releases thecenter pedal, the operator has precise control of the machine.

STMG 775 - 80 -1/04

LeftDriveLoop

RightDriveLoop

Actuator

Brake

RightSteeringValves

FWD BrakeControlValve

TransmissionOverride

Valve

REV

FWD

Motor

Actuator

REV

PilotSpool

DriveMotor

953C POWER TRAIN HYDRAULIC SYSTEMCENTER PEDAL FULLY DEPRESSED

LeftSteeringValves

MotorControl Valve

PumpControlValve

OKTOPU

S57

When the "Hydrostatic Transmission" ECM is selected from the ECM Selector Screen usingCat ET, the technician can gain access to the power train Configuration Screen.

The technician has some limited capabilities to change parameters for the Power Train ECM.Highlight the parameter and then use the "Change" button on the lower left to change theparameter. The parameter for "Parking Brake Lockout Status" can be used for performing ahystat stall test or for servicing the machine. The steering sensitivity can be adjusted using the"Steering Response Rate Setting" parameter.

The Calibration Reset feature resets the track speed and pedal lever calibrations. This featureshould be used whenever one of the electro-hydraulic components that require calibrations arereplaced. The feature may also be used when certain fault codes are present or when thetechnician wants to return the system to known good values.

This feature resets the component values back to the default settings. The component thenneeds to be calibrated. Refer to the Calibration Procedures.

All three parameters can be adjusted or done using the monitor. Refer to the Service Manualfor more information on this Configuration Screen.

STMG 775 - 81 -1/04

OKTOPU

S58

When Calibrations is selected in Cat ET for the hystat transmission the screen shown aboveappears.

The technician can select to one or more of the four calibrations available to calibrate thesteering and brake pedal or the transmission lever.

The technician can also use the toggle switch shown earlier in the right console to perform thesame calibrations.

STMG 775 - 82 -1/04

OKTOPU

S59

963C Implement Hydraulic System

The hydraulic system controls the operation of the bucket and the ripper. The hydraulic systemcan be different from one machine to the next machine according to the optional equipment thatis on the machine. The basic hydraulic system consists of the following components: hydraulictank and filter, hydraulic pump, main control valve group (lift and tilt), third control valve,main relief valve, diverter valve (if equipped), hydraulic cylinders, pressure reducing valve,pilot valve group, and hydraulic oil cooler.

The pressure reducing valve is used to provide pilot oil for the pilot valve group. Charge oilfrom the power train charge pump is used as the supply source for the pilot oil. The valve alsoworks with the shuttle valve and uses lift cylinder oil to create pilot oil to lower the implementswhen the engine is not running.

NOTE: The following illustrations should be used to supplement the materials found inTechnical Instruction Module "953C/963C/973C Track Loaders–Implement Hydraulic System"(SERV2695). The previous training package did not provide cut-away illustrations for the pilotvalves or the implement control valves.

STMG 775 - 83 -1/04

Tank

Pilot ValveGroup

RipperCylinders

DiverterValve

TiltControlValve

LiftControlValve

AttachControlValve

ImplementPump

LiftCylinders

TiltCylinder

Multi-purposeCylinders

PressureReducing

Valve

ShuttleValve

VentedMakeupValve

FloatValve

VacuumBreaker

From Charge Pumps

From Charge Filter Bypassand Charge Relief Valve

From Brake Valve

To Charge Pumps

FromCaseDrain

963C IMPLEMENT HYDRAULIC SYSTEMHOLD

MainReliefValve

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The 963C and 953C use the same pilot valves. Some machines may be equipped with ajoystick-type pilot valve for lift and tilt functions.

In HOLD, springs hold the plungers and stems up. Pilot supply oil is blocked by the stems.The pilot lines from the control valve are open to the tank through the internal passage and thecross-drilled hole in each stem and the spring chamber.

Some of the circuits may use detent coils to hold the lever for certain functions such as FLOATor for the bucket kickouts.

When the lever is shifted, the actuator and rod contacts the plunger and pushes it down againstthe springs and retainer. As the retainer moves down, the springs move the stem down.Depending on how far the actuator is shifted determines how far the stem moves.

STMG 775 - 84 -1/04

Actuator

DetentCoil

Plunger

SpringChamber

Pilot  SupplyPassage

ReturnTo TankPassage

FromControl Valve

ToControl Valve

HOLD SHIFT

Retainer

InternalPassage

FromControl Valve

FromControl Valve

Rod

Hole

Stem

PILOT CONTROL VALVE - JOYSTICK

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As the stem moves down, it will close off the cross-drilled hole and the internal passage fromthe spring chamber. The passage to the control valve is no longer open to the tank. Pilot oilenters the cross-drilled hole and internal passage and flows to the control valve to shift thecontrol spool. The greater the pilot oil flow to the control spool the greater the control spooltravel.

As pressure increases in the pilot line to the control valve, the pressure works on the stem tomove the stem up to a balance position against the springs to maintain the pilot pressure in thepilot line. This will maintain the position of the control spool in the control valve.

When the key start switch is in the ON position, the detent coils are energized.

If the operator shifts the lever further the plate above the rod contacts the detent coil. Theactuator and plate are then held by the detent coil until the operator moves the lever out ofdetent or power to the detent is stopped.

Power may be stopped by "kickout" switches mounted on the cylinders or loader linkage.

STMG 775 - 85 -1/04

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The 963C and 953C use the same pilot valves. Some machines may be equipped with ajoystick for lift and tilt functions as discussed, while other machines use separate levers foreach function. The third function, if equipped, uses the lever-type pilot valve.

In HOLD, springs hold the plungers and stems up. Pilot supply oil is blocked by the stems.The pilot lines from the control valve are open to the tank through the internal passage and cross-drilled hole in each stem and the spring chamber.

Some of the circuits may use detent coils to hold the lever for certain functions such as FLOATor for the bucket kickouts.

When the joystick is shifted, the actuator contacts the plunger and pushes it down against thesprings and retainer. As the retainer moves down, the springs move the stem down. Dependingon how far the actuator is shifted determines how far the stem moves.

STMG 775 - 86 -1/04

Actuator

Detent

Plunger

Stem

Pilot  SupplyPassage

Returnto TankPassage

FromControlValve

ToControlValve

HOLD SHIFT

Retainer

InternalPassage

FromControlValve

FromControlValve

SpringChamber

Hole

PILOT CONTROL VALVE - LEVER

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As the stem moves down, it will close off the cross-drilled hole and the internal passage fromthe spring chamber. The passage to the control valve is no longer open to the tank. Pilot oilenters the cross-drilled hole and internal passage and flows to the control valve to shift thecontrol spool. The greater the pilot oil flow to the control spool the greater the control spooltravel.

As pressure increases in the pilot line to the control valve, the pressure works on the stem tomove the stem up to a balance position against the springs to maintain the pilot pressure in thepilot line. This will maintain the position of the control spool in the control valve.

When the key start switch is in the ON position, the detent coils are energized.

If the operator shifts the joystick further the actuator contacts the detent coil. The actuator isthen held by the detent coil until the operator moves the joystick out of detent or power to thedetent is stopped.

Power may be stopped by "kickout" switches mounted on the cylinders or loader linkage.

STMG 775 - 87 -1/04

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The two open-center control spools in the main control valve group provide the tilt and liftfunctions for the machine. The tilt circuit has flow priority over the lift circuit

The tilt spool has three positions: TILT BACK, HOLD, and DUMP. If the tilt valve spool is inthe HOLD position, the oil will flow around the tilt valve spool to the lift valve spool. The liftvalve spool also has three positions: RAISE, HOLD, and LOWER. When the lift is shifted tofull lower the float vent valve opens to provide FLOAT.

Movement of the lift valve spool and the tilt valve spool is controlled by pressurized pilot oilfrom the pilot valves. Centering springs keep the spools in the HOLD position when the pilotvalves (not shown) are in HOLD.

With tilt valve spool in the HOLD position, pump oil is sent from the supply passage, aroundthe tilt spool to the lift valve spool. When the lift spool is in the HOLD position, the oil flowsaround the lift valve spool to the tank passage.

With the spools in hold the passages to the cylinders are blocked.

STMG 775 - 88 -1/04

TILT HOLD / LIFT HOLD

Supply

Tank

ToPilot

Valves

RodEnd

HeadEnd

Rod End  Head EndLoad

Check Valve 

From FloatValve

Tilt  Spool

Lift  Spool

MakeupValve

FloatVent  Valve

LoadCheck Valve 

ToPilot

Valves

963C MAIN CONTROL VALVE GROUP

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When the tilt control lever is moved to the TILT BACK position, pilot oil is sent to the pilotchamber on the right end of the tilt spool to shift the spool to the left. Supply oil is blockedfrom going to the lift spool and the rod end of the tilt cylinder is open to the tank around bothspools.

Pressure increases in the supply passage and unseats the tilt load check valve. Supply oil isthen directed to the head end of the tilt cylinder. Return oil from the rod end flows to the tank.The bucket tilts back.

As the oil from the rod end of the tilt cylinder bypasses the tilt spool and the lift spool, the TiltBack Operation and the Raise Operation are prevented from occurring at the same time. Whentilt valve spool is in the full TILT BACK position, no pressure oil flows to the lift valve spool.The lift circuit is inoperable.

STMG 775 - 89 -1/04

963C MAIN CONTROL VALVE GROUPTILT BACK / LIFT HOLD

Supply

FromPilotValve

Tank

ToPilot

Valves

RodEnd

HeadEnd

Rod End  Head EndLoad

Check Valve 

From FloatValve

Tilt  Spool

Lift  Spool

MakeupValve

FloatVent  Valve

LoadCheck Valve 

ToPilotValve

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S64

When the lift control lever is moved to the RAISE position, pilot oil from the pilot valve shiftsthe lift spool to the right. Oil from the main pump is directed from the inlet supply passagearound the tilt spool to the lift spool. Supply oil is blocked from going to the tank and the rodend of the lift cylinders are open to the tank around the lift spool.

Pressure increases in the supply passage and unseats the lift load check valve. Supply oil isthen directed to the head end of the lift cylinders. Return oil from the rod ends flows to thetank causing the lift arms to raise.

STMG 775 - 90 -1/04

Rod End  Head End

Supply

FromPilotValve

Tank

ToPilot

Valves

RodEnd

HeadEnd

LoadCheck Valve 

Tilt  Spool

Lift  Spool

MakeupValve

FloatVent  Valve

LoadCheck Valve 

ToPilotValve

From FloatValve

963C MAIN CONTROL VALVE GROUPTILT HOLD / LIFT RAISE

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If the full TILT BACK is activated while the lift spool has been shifted, there is no supply oilavailable to operate the lift circuit. The lift load check valve seats and the lift cylinders stopmoving. The tilt circuit has flow priority over the lift circuit.

If the tilt spool is partially shifted for TILT BACK, there will be some supply oil available forthe lift to RAISE. The lift cylinder speed will be dramatically reduced.

In typical truck loading operations, the operator will shift the lift pilot valve lever into the raisedetent position and then operate the tilt pilot lever to maximize the bucket load while loading.When the bucket breaks free of the pile, the operator releases the tilt pilot lever and the raisecircuit keeps moving until the bucket reaches the "lift kickout." When this occurs, power is cutto the detent coil in the pilot valve and the load is ready to be dumped into a truck.

STMG 775 - 91 -1/04

963C MAIN CONTROL VALVE GROUPTILT BACK / LIFT RAISE

Supply

FromPilotValve

Tank

ToPilotValve

RodEnd

HeadEnd

Rod End  Head EndLoad

Check Valve 

From FloatValve

Tilt  Spool

Lift  Spool

MakeupValve

FloatVent  Valve

LoadCheck Valve 

ToPilotValve

FromPilotValve

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S66

When tilt DUMP and lift RAISE are required at the same time, return oil from the head end ofthe tilt cylinder is directed to the lift spool to provide supply oil for the lift circuit.

STMG 775 - 92 -1/04

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S67

When the lift control lever is moved to the FLOAT position, the lift spool is moved to the leftby pilot oil. At the same time, the solenoid on the float valve (not shown) is energized to openthe vent passage below the float vent valve to the tank.

The vent valve opens due to the pressure differential. Oil flow opens the vent valve. With thevent valve open the rod end of the lift cylinders is open to the tank. The head end of the liftcylinders are also open to tank around the lift spool.

Supply oil from the pump unseats the lift load check valve and also flows around the lift spooland the float vent valve to the tank. This action keeps the oil in the cylinders slightlypressurized to create some down pressure on the bucket to improve backdragging.

STMG 775 - 93 -1/04

Supply

FromPilotValve

Tank

ToPilot

Valves

RodEnd

HeadEnd

Rod End  Head EndLoad

Check Valve 

To FloatValve

Tilt  Spool

Lift  Spool

MakeupValve

FloatVent  Valve

LoadCheck Valve 

ToPilotValve

963C MAIN CONTROL VALVE GROUPTILT HOLD / LIFT FLOAT

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If the 963C is equipped with an attachment circuit to use with a ripper or multi-purpose bucket,the circuit has flow priority over the tilt and lift circuits.

Operation of the attachment valve is the same as the tilt circuit except for not having a makeupvalve.

When the attachment spool is shifted fully, as shown, no supply oil is available to the tilt andlift circuits. If the attachment spool is partially shifted, some supply oil is available for the tiltand lift circuits. The tilt and lift cylinder speeds will be dramatically reduced.

When the attachment valve is shifted to the left (not as shown) return oil from the rod end isavailable as supply oil for the tilt and lift circuits.

STMG 775 - 94 -1/04

FromPilotValve

Head End

LoadCheck Valve 

AttachmentSpool Supply 

Rod End To Tilt  Valve

ToPilotValve

ToPilotValve

HOLD

SHIFT

963C ATTACHMENT CONTROL VALVE

Head End

LoadCheck Valve 

AttachmentSpool Supply 

Rod End To Tilt  Valve

ToPilotValve

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ADVANCED OPTIONAL SYSTEMS

The updated 953C and 963C can be equipped with the optional Machine Security System.When the anti-theft feature is installed, a microchip is imbedded in the rubber grip of the key.This microchip responds to a signal sent from an antenna around the start/stop switch (key slot).Only if the key has the appropriate, pre-programmed microchip can the engine be started.

The wrong microchip or no microchip will not allow electrical power to be sent to the mainpower relay or the starter relay, preventing the engine from being started. The wrong microchipwill also disable the ADEM III electronic governor, shutting off fuel to the engine so thatsimply bypassing the starter relay will not start the engine.

When the "MSS" ECM is selected from the ECM Status Summary Screen using Cat ET, thetechnician can gain access to the Machine Security System configuration screen.

Highlight the parameter and then use the "Change" button on the lower left to change theparameter. Refer to the Service Manual for more information on this configuration screen andthe Machine Security System.

STMG 775 - 95 -1/04

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The 953C and 963C can be equipped with the optional Product Link System.

When the "Product Link" ECM is selected from the ECM Status Summary Screen using CatET, the technician can gain access to the the the Product Link System configuration screen.

Highlight the parameter and then use the "Change" button on the lower left to change theparameter.

STMG 775 - 96 -1/04

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Scroll down on the screen to access the remaining parameters.

Refer to the Service Manual for more information on these configuration screens and theProduct Link System.

STMG 775 - 97 -1/04

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SSIGNIFICANT MAINTENANCE CHANGES

A new optional attachment on the 953C and 963C is the Rotating Bushing Track (RBT). Thisoption is a sealed and lubricated system which includes four track seals per joint, non-restrainedrotating bushings, longer track pins, redesigned track links with wider pin bosses and bushingstraps, and taller rails. It has a unique pin retention system. The rotating bushing virtuallyeliminates relative motion between the bushing and sprocket teeth.

The minimal bushing wear that does occur is evenly distributed around the bushing. Therefore,no bushing turn is required and sprocket wear is dramatically reduced. RBT significantlyincreases bushing and sprocket life in abrasive soil conditions.

The standard equipment track links on the 963C are the newest generation of Extended WearLife (EWL) track. These new links include even more wear material for even longer track lifethan the original EWL track. Each 963C link has a center strut to help carry the machine load.

A two-piece, split master-link allows easy track chain removal and installation should it benecessary to break the track chain. Disassembly of this link is significantly faster and easierthan removing a pressed-in track pin, reducing service time and cost for the customer.

Tough Steel™ sprocket segments are a new addition to the machines. Five Tough Steelsegments are bolted onto each final drive sprocket hub. These segments can be removed orreplaced without breaking the track. Each segment has five teeth. When the track chain travelsover the sprocket, it is driven by every second sprocket tooth so two complete revolutions ofthe final drive are necessary for each tooth to contact a bushing once. The result is long, even,wear of the sprocket teeth.

72

STMG 775 - 98 -1/04

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SNEW TOOLING/SKILLS REQUIRED FOR SERVICE

Due to the high pressures that may be reached when testing the hystat drive loops the pressuretaps (arrow) are larger than what are used on lower pressure circuits.

To test the hystat system the following parts and tooling are suggested:

4 - 187-3546 quick couplers

2 - 177-7865 high pressure hoses

2 - 8T0861 pressure gauges

2 - 171-1879 adapters

2 - 187-3547 nipples

When assembled, two of the test ports can be checks at the same time. Double the quantitiesabove to test all four ports.

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STMG 775 - 99 -1/04

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SCONCLUSION

This concludes the presentation on the updated 953C and 953C Track Loaders with Tier IIengines.

This presentation supports the service manual and previous released training materials. Whenused in conjunction with the service manual, the information in this package should permit thetechnician to do a thorough job of analyzing a problem in these systems.

For service repairs, adjustments, and maintenance, always refer to the Owner and OperatorManual, Service Manuals, and other related service publications.

74

STMG 775 - 100 -1/04

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SHYDRAULIC SCHEMATIC COLOR CODES

The colors on the hydraulic schematics and cross-sectional views shown throughout thispresentation denote specific meanings. This illustration identifies the meaning of each color.

STMG 775 - 101 -1/04

Dark Gray - Cutaway section

Light Gray -  Surface color 

Red - High pressure oil

Red/White Stripes -  1st pressure reduction

Red Crosshatch - 2nd reduction in pressure

Pink - 3rd reduction in pressure

Red/Pink Stripes - Secondary source oil pressure

Orange - Pilot, signal, or Torque Converter oil

Orange/White Stripes -Reduced pilot, signal, or TC oil pressure

Green - Tank, sump, or return oil Blue - Trapped oil

Brown - Lubricating oil

Purple - Pneumatic pressure 

Orange Crosshatch - 2nd reduction inpilot, signal, or TC oil pressure.

White -  Atmosphere orAir (no pressure)

Yellow - Moving or activated components 

Cat Yellow - (restricted usage)Identification of componentswithin a moving group 

Black - Mechanical connection.  Seal 

Green/White Stripes -Scavenge Oil or Hydraulic Void

HYDRAULIC SCHEMATIC COLOR CODE

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STMG 775 - 102 -1/04

1. 963C model view2. 95C model view3. Similarities and Differences Chart4. Seat5. Left console6. Fuse panel7. Dash and instrument panel8. Instrument display9. Service switches

10. Steering and brake pedals11. Joystick controls12. Lever controls13. Right console and compartment14. 953C fuel tank15. 953C hydraulic tank16. 963C hydraulic tank17. Radiator and ATTAC18. Right side engine compartment19. Case drain filters20. Power Train ECM21. Batteries22. Left side below cab23. Left side engine compartment24. 3126B engine25. Engine ECM26. Engine speed sensor27. Cat ET ECM summary screen28. Engine configuration screen29. 963C hydraulic block diagram30. 953C hydraulic block diagram31. Hystat pumps32. Hystat taps on pump33. ECM manifold34. Implement pilot accumulator35. 953C hystat accumulator and implement tap36. 963C hystat motor with speed sensor37. 963C hystat motor with flushing valve38. 963C Left Drive Loop39. Power Train ECM Manifold40. 963C Pressure Fitting Locations41. 963C Power Train Hydraulic System -

PARK42. 963C Power Train Hydraulic System -

BRAKES RELEASED43. 963C Power Train Hydraulic System -

MAXIMUM FORWARD44. 963C Power Train Hydraulic System -

RIGHT TURN FORWARD45. 963C Power Train Hydraulic System -

ILLUSTRATION LIST

RIGHT SPOT TURN46. 963C Power Train Hydraulic System -

CENTER PEDAL PARTIAL DEPRESSED47. 963C Power Train Hydraulic System -

CENTER PEDAL FULLY DEPRESSED48. 953C Left Drive Loop49. 953C Pressure Tap Locations50. 953C Power Train Hydraulic System -

PARK51. 953C Power Train Hydraulic System -

BRAKES RELEASED52. 953C Power Train Hydraulic System -

MAXIMUM FORWARD53. 953C Power Train Hydraulic System -

RIGHT TURN FORWARD54. 953C Power Train Hydraulic System -

RIGHT SPOT TURN55. 953C Power Train Hydraulic System -

CENTER PEDAL PARTIAL DEPRESSED56. 953C Power Train Hydraulic System -

CENTER PEDAL FULLY DEPRESSED57. Hystat Configuration Screen in Cat ET58. Hystat Calibrations59. 963C Implement Hydraulic System60. Pilot Control Valve - Joystick61. Pilot Control Valve - Lever62. 963C Main Control Valve Group - TILT

HOLD/LIFT HOLD63. 963C Main Control Valve Group - TILT

BACK/LIFT HOLD64. 963C Main Control Valve Group - TILT

HOLD/LIFT RAISE65. 963C Main Control Valve Group - TILT

BACK/LIFT RAISE66. 963C Main Control Valve Group - TILT

DUMP/LIFT RAISE67. 963C Main Control Valve Group - TILT

HOLD/LIFT FLOAT68. 963C Attachment Control Valve69. Machine Security System Screen70. Product Link Screen71. Product Link Screen (continued)72. Undercarriage73. Pressure taps74. 953C model view

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STMG 775 - 103 - Handout No. 11/04

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Machine Walk-around Checklist

Directions: Use this sheet when performing a machine orientation lab exercise.

Place a check in the blank if the fluid level is acceptable.

953C 963CEngine oil levelHydraulic system oil levelCooling system fluid level Pump drive (splitter box) fluid level Fuel level

Place a check in the blank if acceptable or after task was performed.

953C 963CDrain water separatorCheck seat beltCheck air filter indicator and pre-cleaner

Place a check in the blank after locating each of the following controls.

953C 963CLeft steering pedalRight Steering PedalService brake pedalParking brake leverTransmission control leverLoader lift and tiltAttachment lever Diverter valve lever (if equipped)

Place a check in the left blank after locating each of the following identification plates. Fill inthe right blank with number requested.

953C Machine Serial Number 953C Engine Serial Number

963C Machine Serial Number 963C Engine Serial Number

STMG 775 - 104 - Handout No. 21/04

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Machine Walk-around Checklist (continued)

Directions: Use this sheet when performing a machine orientation lab exercise.

Place a check in the blank after locating and reading the following warnings label on themachine.

953C 963CBefore operatingUse of etherAccumulatorsBefore roading Loader arm braceROPSUse of Jumpers

STMG 775 - 105 - Handout No. 31/04

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Electrical/Electronic Reference Handout - Cab

Switches:

Governor control switch: sends operator inputs about the desired engine rpm to theADEM III Electronic Engine control, which communicates with the MAC-14 to controlthe hydrostatic drive system.

Speed/direction control lever: brake-on switch is activated when the speed/directionlever is in the "BRAKE-ON" position, venting pressure to the brake release actuatorpiston.

Parking brake switch: on the left console for the operator to apply or disengage theparking brakes.

Disconnect switch: disconnects the batteries from the entire machine electrical system.

Rear wiper switch: activates the rear wiper.

Front wiper switch: activates the front wiper. It has an intermittent wiper feature.

A/C blower switch: is a seven position switch for selecting one of three blower speeds;three speeds for A/C, one position off, three speeds for heating.

Forward horn switch: activates the forward horn.

Key start switch: starts the 3126B engine by signaling the ADEM III engine controllerand supplies power for all electrical components. This switch is also used to stop theengine.

MSS Anti-theft key start switch: available as an attachment.

Numeric Message Display switch: allows the operator to scroll through differentinformation on the 963C monitoring system Numeric Message display (hour meter,engine rpm, override pressure, odometer).

Lamp switch: turns on the instrument panel lights and the outside lights.

Service switch: is one of three Service Mode switches located below the right armrest.The switch is used for accessing on-board fault codes and service information history,and for calibrating various machine functions.

Clear switch: one of the three Service Mode switches, is used to clear fault codes.

Sensor/speed calibrate switch: the third Service Mode switch and is used forcalibrations.

Case drain filter bypass switch: illuminates the monitoring system warning light ifhydraulic oil is bypassing the case drain filter.

Charge filter bypass switch: illuminates the monitoring system warning light ifhydraulic oil is bypassing the charge filter.

STMG 775 - 106 - Handout No. 41/04

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STMG 775 - 107 - Handout No. 51/04

Electrical/Electronic Reference Handout - Inputs

Sensors:

Hydraulic oil temperature sensor: is used to measure the temperature of the oil in thehydraulic tank. This information is available on one of the gauges of the 963Cmonitoring system, and activates one of the monitoring system warning lights.

Override pressure sensor: sends the Override pressure data from the drive loops to thePower Train ECM and activates a warning indicator on the monitoring system.

Engine speed sensor: provides the engine rpm data to the Power Train ECM and theADEM III Engine control.

Left/right pilot pressure sensors: senses pressure in the left and right resolvers todetect a stuck solenoid.

Left/right travel motor rpm sensors: located on the travel motors, provide the trackspeed to the Power Train ECM.

Left/right steering pedal sensors: provide the positions of the steering pedals to thePower Train ECM, which controls the power train accordingly.

Brake pedal sensor: provides the position of the center brake pedal to the Power TrainECM, which controls the hydrostatic drive system and brake solenoid accordingly.

Speed/direction lever sensor: provides the position of the speed/direction lever (reverseV-pattern) to the Power Train ECM, which controls the power train accordingly.

Coolant level sensor: sends a signal to the monitoring system, which controls a light onthe instrument panel to indicate if the engine coolant level is adequate before the engineis started.

Senders:

Fuel level sender: provides fuel quantity information to the monitoring system gaugeand one of the indicator lights.

Pump drive (splitter box) oil temperature sender: provides the temperature of thepump drive oil to one of the gauges of the monitoring system, and one of the indicatorlights.

Engine oil pressure sender: provides information to one of the monitoring systemwarning lights and to the ADEM III engine control. The monitoring system stores and"Tattletales" engine oil pressure as if it were a gauge.

Engine coolant temperature sender: provides the temperature of the coolant in theengine to the ADEM III, the monitoring system and the gauge on the instrument panel.

Hydraulic oil temperature sender: provides the temperature of the hydraulic oil to themonitoring system and to the gauge on the instrument panel.

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Engine Air Inlet and Exhaust System Component Identification

Directions: Use this worksheet during the visual presentation to take notes on the location and function of thecomponents. During the lab exercise, place a check in the blank as each component is identified on the machine.If letters or numbers are used for component identification enter it in the blank instead. After locating thecomponents use the Parts Manual or SIS and record the part name and number as time allows

1. Manifold (boost) pressure sensor

Location:

Function:

Parts Manual Name Part No.

2. Air inlet temperature sensor

Location:

Function:

Parts Manual Name Part No.

3. Air filter indicator

Location:

Function:

Parts Manual Name Part No.

4. Pre-cleaner

Location:

Function:

Parts Manual Name Part No.

5. Exhaust Manifold

Location:

Function:

Parts Manual Name Part No.

6. Turbocharger

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 108 - Handout No. 61/04

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7. Air to air aftercooler

Location:

Function:

Parts Manual Name Part No.

8. Air inlet heater (AIH)

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 109 - Handout No. 71/04

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Engine Fuel System Component Identification

Directions: Use this worksheet during the visual presentation to take notes on the location and function of thecomponents. During the lab exercise, place a check in the blank as each component is identified on the machine.If letters or numbers are used for component identification enter it in the blank instead. After locating thecomponents use the Parts Manual or SIS and record the part name and number as time allows

1. Priming pump

Location:

Function:

Parts Manual Name Part No.

2. Primary fuel filter/water separator

Location:

Function:

Parts Manual Name Part No.

3. Secondary fuel filter

Location:

Function:

Parts Manual Name Part No.

4. Fuel shutoff lever (if equipped)

Location:

Function:

Parts Manual Name Part No.

5. Injectors

Location:

Function:

Parts Manual Name Part No.

6. HEUI pump

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 110 - Handout No. 81/04

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7. Engine ECM

Location:

Function:

Parts Manual Name Part No.

8. Ether start solenoid

Location:

Function:

Parts Manual Name Part No.

9. Speed timing sensor

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 111 - Handout No. 91/04

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Engine Lubrication System Component Identification

Directions: Use this worksheet during the visual presentation to take notes on the location and function of thecomponents. During the lab exercise, place a check in the blank as each component is identified on the machine.If letters or numbers are used for component identification enter it in the blank instead. After locating thecomponents use the Parts Manual or SIS and record the part name and number as time allows

1. Oil pressure sensor

Location:

Function:

Parts Manual Name Part No.

2. Oil filter

Location:

Function:

Parts Manual Name Part No.

3. Oil cooler

Location:

Function:

Parts Manual Name Part No.

4. Crankcase breather

Location:

Function:

Parts Manual Name Part No.

5. Dipstick

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 112 - Handout No. 101/04

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Cooling System Component Identification

Directions: Use this worksheet during the visual presentation to take notes on the location and function of thecomponents. During the lab exercise, place a check in the blank as each component is identified on the machine.If letters or numbers are used for component identification enter it in the blank instead. After locating thecomponents use the Parts Manual or SIS and record the part name and number as time allows

1. Radiator

Location:

Function:

Parts Manual Name Part No.

2. Coolant level sight gauge

Location:

Function:

Parts Manual Name Part No.

3. Coolant fill/recovery tank

Location:

Function:

Parts Manual Name Part No.

4. Radiator cap

Location:

Function:

Parts Manual Name Part No.

5. Coolant temperature sensor

Location:

Function:

Parts Manual Name Part No.

6. Water pump

Location:

Function:

Parts Manual Name Part No.

7. Coolant thermostat

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 113 - Handout No. 111/04

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Electrical Component Identification

Directions: Use this worksheet during the visual presentation to take notes on the location and function of thecomponents. During the lab exercise, place a check in the blank as each component is identified on the machine.If letters or numbers are used for component identification enter it in the blank instead. After locating thecomponents use the Parts Manual or SIS and record the part name and number as time allows

1. Batteries

Location:

Function:

Parts Manual Name Part No.

2. Disconnect switch

Location:

Function:

Parts Manual Name Part No.

3. Alternator

Location:

Function:

Parts Manual Name Part No.

4. Starter motor

Location:

Function:

Parts Manual Name Part No.

5. Starter relay

Location:

Function:

Parts Manual Name Part No.

6. Alternator breaker

Location:

Function:

Parts Manual Name Part No.

7. Diagnostic connector

Location:

Function:

Parts Manual Name Part No.

STMG 775 - 114 - Handout No. 121/04

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STMG 775 - 115 - Handout No. 131/04

Basic Engine Checks

Directions: Using the Service Manual, perform the test according to the procedure in the Service Manual. Recordthe specifications and the results from the test in the chart below.

Machine Model Date

Machine Serial Number SMU

VISUAL CHECKS:

Leaks? Damage?

BASIC CHECKS

CHECKS COMMENTS

Engine Oil Level

Fuel Level

Drain Fuel Filter/Water Separator

Coolant Level

Air Filter Indicator

Pre-cleaner (if equipped)

Check Radiator for Debris

Check Belts

Check Battery Cables

Check Harness Connections

Check for Leaks

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Posttest: Machine Orientation

NOTE: Besides the information in this presentation you may use sales informationbrochures (specalogs) to answer the following questions.

I. Directions Modified True / False: If the question is false, circle the word or words thatmake the statement incorrect and replace with the word(s) to make the statement correct.

1. The Tier II engine used in 953C and 963C is a 3126B equipped with a HEUI fuelsystem.

2. The electronically controlled engine uses a MAC-14 controller.

3. The monitoring system is flashable using Cat ET on the updated 953C and 963CTrack Loaders.

4. The hystat pumps and the implement pump did not change from the previousmachine.

5. The Engine ECM will always start the machine at High Idle.

6. The hystat system can be calibrated using switches found in the right console orthrough Cat ET.

7. The diverter valve is solenoid controlled.

8. An optional electric fuel priming pump is available

9. The 963C uses one case drain filter.

10. Engine speed was reduced on the 953C and 963C with a Tier II engine.

11. The three engine calibrations that can be done using Cat ET are: Injector CodeCalibrations, Pressure Sensor Calibration, and Timing Calibration.

12. The brake solenoid is mounted to the synchronization manifold.

13. Rotating Bushing Track (RBT) is standard on the 953C and 963C.

14. Maintenance intervals have been extended on the updated machine.

15. The 953C and 963C may be equipped with 5 ECM's.

STMG 775 - 116 - Handout No. 141/04

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STMG 775 - 117 - Handout No. 151/04

Function

A. Limits maximum pressure in the charge circuit.

B. Regulates flow of oil from the drive loops forflushing and cooling the motors.

C. Relieves drive motor actuator pressure to maintaintorque at high drive pressure on the 963C.

D. Transfers power from the engine to the pumps.

E. Variable displacement and bi-directional flow.Converts hydraulic horsepower into mechanicalhorsepower.

F. Allows pressures to equalize between both driveloops during straight travel.

G. Controlled by signal oil from a steering solenoid onthe 953C.

H. Controls the signal pressure to the pump actuatoron a 963C.

I. Variable displacement, bi-directional flow.Converts mechanical horsepower into hydraulichorsepower.

J. Constant displacement. Supplies the power trainwith charge oil pressure.

K. These allow charge pressure to pressurize the lowpressure side of the drive loops. They also limitdrive loop maximum pressure.

L. Controls the minimum pressure in the low pressuredrive loop.

M. When the Power Train ECM senses a fault, thisvalve is de-energized to block flow to the steeringsolenoids.

Component

I Hystat drive pumps

J Charge pumps

H Pump control valve

E Drive motors

B Drive motor flushingvalve

M Transmission overridesolenoid

C Drive motor pressureoverride valve

L Flushing relief valve

A Charge relief valve

K Makeup/crossover reliefvalves

G Pilot spool in the pump

D Splitter box/pump drive

F Synchronization valve

Posttest: 953C/963C Track Loader Hystat Components and Functions

Directions: Match each component to the correct function.

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STMG 775 - 118 - Handout No. 161/04

Function

A. A vane-type pump. This pump supplies the implementsystem with hydraulic oil.

B. Allows full charge pressure to reach the implementcontrol levers. This component limits the maximumpressure allowed to reach the implement controllevers.

C. A gear-type pump that supplies the pilot circuit.

D. Send pilot signals to the main control valve spools tocontrol implement cylinder movement.

E. This valve group directs main system oil flow to thehydraulic cylinders.

F. Cools the hydraulic oil used in the implement system

G. This system has a single warning light for thehydraulic system temperature.

H. Manually set to divert implement oil from themultipurpose bucket to the ripper cylinders.

Component

D Attachment functionlevers

M Caterpillar MonitoringSystem

E Main control valve group

B Hydraulic system pressurereducing valve

N Manual diverter valve

C Pilot pump

A Implement pump

K Implement hydraulic oilcooler

Posttest: 953C/963C Track Loaders Hydraulic System Components andFunctions

Directions: Match each component to the correct function.

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Posttest - Answers

Machine Orientation

I. Modified True / False:T 1.

F 2. ADEM-IIIT 3.

F 4. The implement pump is larger. F 5. Low Idle. F 7. manually controlled.

T 8.T 9.T 10.T 11.

F 12. ECM manifold. F 13. optional

T 14.T 15.

953C/963C Track Loaders Hystat Components and Functions

I Hystat drive pumps

J Charge pumps

H Pump control valve

E Drive motors

B Drive motor flushing valve

M Transmission override solenoid

C Drive motor pressure override valve

L Flushing relief valve

A Charge relief valve

K Makeup/crossover relief valves

G Pilot spool in the pump

D Splitter box/pump drive

F Synchronization valve

STMG 775 - 119 - Handout No. 171/04

953C/963C Track Loaders HydraulicSystem Components and Functions

D Attachment function levers

M Caterpillar Monitoring System

E Main control valve group

B Hydraulic system pressure reducingvalve

N Manual diverter valve

C Pilot pump

A Implement pump

K Implement hydraulic oil cooler