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2-1
2 Power Transmission System1. Clutch .....................................................................2-2[1] Structure and operation .........................................2-2
(1) Clutch unit .........................................................2-2(2) Clutch operation mechanism .............................2-4(3) Clutch start system ............................................2-6
[2] Checks and maintenance ......................................2-6(1) Pedal stroke check ............................................2-6(2) Pedal allowance check ......................................2-6(3) Check of the pedal and floor plate clearance
when the clutch is disengaged ..........................2-7(4) Clutch start system check .................................2-7(5) Clutch start switch check ...................................2-7(6) Clutch disc .........................................................2-8(7) Clutch fluid air bleeding .....................................2-8
[3] Failure diagnosis ...................................................2-9(1) Engagement defect ...........................................2-9(2) Slipping..............................................................2-9(3) Unsmooth engagement .....................................2-9(4) Sudden forward movement (jumping out) .........2-9(5) Abnormal noise .................................................2-9
2. Manual transmission ..........................................2-10[1] Structure and operation .........................................2-12
(1) Gear change....................................................2-12(2) Gear ratio ........................................................2-13(3) Shift lever ........................................................2-14(4) Transmission operation ...................................2-15(5) Mechanisms for safe driving............................2-21(6) Internal transmission lubrication ......................2-27
[2] Overhaul ..............................................................2-27(1) Important points for disassembly ........................... 2-27(2) Check of internal transmission parts ...............2-27(3) Important points for assembly .........................2-28
[3] Failure diagnosis .................................................2-28(1) Abnormal noise ...............................................2-28(2) Gear engagement and disengagement
problems .........................................................2-29(3) Gear jump out..................................................2-29(4) Oil leaks...........................................................2-29
3. Transfer ................................................................2-30[1] Structure and operation .......................................2-31
(1) Part-time 4WD, separate from the transmission (Jimny: SN413) ..........................2-31
(2) Full-time 4WD (Swift: RS413) .........................2-35(3) Full-time 4WD (Grand Vitara: JB420) ..............2-36(4) Synchro-mechanism........................................2-41
[2] Checks and maintenance ....................................2-43
4. Drive shaft ...........................................................2-44[1] Structure and operation .......................................2-44
(1) Drive shaft .......................................................2-44(2) Constant velocity universal joint ......................2-44
[2] Checks and maintenance ....................................2-45(1) Drive shaft .......................................................2-45(2) Constant velocity universal joint ......................2-46
5. Propeller shaft .....................................................2-47[1] Structure and operation .......................................2-48
(1) Propeller shaft .................................................2-48(2) Center bearing.................................................2-48(3) Universal joint ..................................................2-49
[2] Checks and maintenance ....................................2-49(1) Propeller shaft check .......................................2-49(2) Universal joint check .......................................2-49(3) Important points for propeller shaft
disassembly (Jimny: SN413) ...........................2-50(4) Important points for propeller shaft
assembly (Jimny: SN413) ...............................2-50(5) Important points for center bearing
disassembly (Swift: RS413) ............................2-51(6) Important points for center bearing
assembly (Swift: RS413) .................................2-52
6. Differential ...........................................................2-53[1] Structure and operation .......................................2-54
(1) Differential (rear of FR vehicles and 4WD vehicles) .................................................2-54
(2) Differential in FF vehicles ................................2-56[2] Checks and maintenance ....................................2-56
(1) Backlash check ...............................................2-56(2) Teeth contact check.........................................2-56(3) Differential assembly (Jimny: SN413
(Rear)) .............................................................2-58(4) Failure diagnosis .............................................2-62
2-2 2 Power Transmission System
1. ClutchThe clutch is positioned between the engine and the transmission. It transmits the engine power using the frictional force between the clutch disc and plate, and the force that pushes down these parts. The clutch is made up of an operation mechanism, which transmits the operation force of the driver through wires or hydraulic pressure, and a clutch unit that receives this force and connects and disconnects the power transmission.
[1] Structure and operation(1) Clutch unit1) Clutch unit structureThe clutch unit components include a clutch disc, clutch cover and release bearing.
3002
Clutch disc
Clutch cover
Release bearing
Pressure plate
Diaphragm spring
A diaphragm spring and a pressure plate are assembled to the clutch cover. They are fixed to a
flywheel with bolts.
The clutch disc is installed between the flywheel and clutch cover (pressure plate), and is fitted into
the transmission input shaft and splines.The clutch disc is press fitted between the flywheel
and pressure plate by the spring force of the diaphragm spring.In other words, the engine power is transmitted to the transmission input shaft via the frictional force between the clutch disc, flywheel and pressure plate.
Clutch operating cylinder
Clutch housing
Clutch cover
Clutch master cylinder
3P50
Clutch pedal
Flywheel
Engine
Release fork
Release bearing
Input shaft
Clutch disc
Transmission
2-32 Power Transmission System
Cushion plateThe clutch facing is riveted together while sandwiching a curved cushion plate. When the clutch is connected suddenly, the bending of the cushion plate absorbs the impact, resulting in a smooth power transmission.
3) Diaphragm spring clutch operationWhen the clutch is connected, the spring force of the diaphragm spring pushes the clutch disc strongly against the flywheel via the pressure plate.
This means that the clutch plate rotates together with the flywheel so that the power from the engine
is always transmitted to the transmission.When the driver steps on the clutch pedal to cut off the power, the release fork pushes the release bearing against the end of the diaphragm spring. At this time, the pivot ring (wire ring) becomes
the fulcrum and the diaphragm spring outer circumference bends back. The retracting spring (retainer plate) moves the pressure plate to the
right. Because this creates a gap between the
friction surfaces of the clutch disc, the power from the engine is cut off.
Clutch facing
Rivet
Damper spring
Clutch hub
Clutch disc
Damper spring(absorbs the impact)
3003
Cushion plate
Facing
Rivet
3004
2) Clutch disc structure- Clutch discClutch facing, which is a frictional material, is
riveted to both sides of the clutch disc. There is a clutch hub in the center of the clutch disc into which the transmissions input shaft is inserted.The clutch facing must have an appropriate friction coefficient. Its friction coefficient must not change much with temperature variations.
- Damper springThe clutch hub is sandwiched between plates to its front and rear, and is constructed so that the clutch can move in a circle (rotation direction) via the
damper spring. It absorbs and dampens the rotation impact when the clutch is connected.
Clutch cover
Diaphragm spring
Flywheel
Retracting spring
Clutch disc
Pressure plate
When the clutch is connected
When the clutch is cut off
Clutch cover
Pivot ring
Release bearing
Release fork
End of diaphragm spring
Clutch disc
Pressure plate
3005
2-4 2 Power Transmission System
(2) Clutch operation mechanism1) Mechanical operation mechanismIn this system, the clutch pedal and release fork are connected with a clutch cable.When the driver steps on the clutch pedal (1), the
clutch cable is pulled (2) (3), and the release fork
pushes the release bearing onto the diaphragm spring (4).
When the driver releases the clutch pedal, the spring force of the return spring and diaphragm spring returns the release fork and clutch pedal to their home positions and power is transmitted to the transmission.
- Master cylinderThe master cylinder is made up of a cylinder section in which a piston slides a long distance, and a reservoir tank that stores the clutch fluid. The master cylinder generates the hydraulic pressure for operating the clutch. To generate the hydraulic pressure, when the driver steps a little on the clutch pedal, the piston is pushed and the clutch fluid inside the cylinder is sent
to the reservoir tank. When the driver steps more on the clutch pedal, the piston moves and releases the connecting rod, which up to now had been pulled by the spring retainer. The spring force of the small conical spring that is built in to the connecting rod moves the inlet valve to the left and cuts off the inlet return common port. At the same time, the fluid pressure inside the cylinder rises rapidly. The clutch fluid is sent
to the operating cylinder and moves the release piston.
3006
Clutch cable
Adjust nut
Clutch pedal
(1)
(2)
(4)
(3)
Release fork
3007
Pipe
Flexible hoseMaster cylinder
Clutch pedal
Release cylinder
Release fork
(1)
(2)
(4)
(3)
When the driver releases the clutch pedal, the piston is returned by the spring force of the return spring and the hydraulic pressure drops. This makes the clutch fluid return from the operating cylinder side. Also, because the spring retainer pulls the connecting rod, the inlet valve opens the inlet return common port. This connects the reservoir tank with the master cylinder, and the master cylinder is filled with clutch fluid.
2) Hydraulic operation mechanismThe components of this system include a clutch pedal, master cylinder, release cylinder, release fork and pipe. The pedal force (1) (2) is transmitted by
hydraulic pressure (3) to the release fork (4).
The hydraulic operation mechanism delivers reliable operation that is light and smooth. However, it has a
complex structure, and if air enters the clutch fluid,
it results in improper operation in the same way as in the brake hydraulic system (becomes difficult to
disengage the clutch). Attention must also be paid
to the clutch fluid level.
Piston
Reservoir tank
Inlet return common port To the operating
cylinder
Spring retainer
Connecting rod
Inlet return common port
Inlet valve
Conical spring
3P43
3P44
Inlet return common port From the operating
cylinder
Spring retainer
Piston
Connecting rod
Inlet return common port
Conical spring
Inlet valve
Reservoir tank
2-52 Power Transmission System
- Principle of leverage The principle of leverage is the way that
a small force changes to a large force depending on the distance ratio between the fulcrum, effort (point of force) and load (point
of operation). This principle of leverage
applies to the clutch pedal, release fork and diaphragm spring.
Also, if the movement distances of the load and effort are l1 and l2, respectively, then:
This means that the long but light movement of the clutch pedal can be used to operate the shor t but heavy movement of the pressure plate.
- Pascals principle When pressure of a certain force per unit
area is applied to one area of a fluid in a sealed container, regardless of its shape, the pressure is transmitted undiminished to all areas of the fluid.
When pressure is applied to a sealed fluid,
force of the same strength (force per unit area) is generated in all parts.
Using this Pascals principle, the force
is increased by making the area of the operating cylinder larger than the master cylinder.
L1
F1
F2
L2
Effort
Fulcrum
Load
3011
Area 20cm2
Force 100N
Area 10cm2
Force 50N
Operating cylinder
Master cylinder
3012
The balanced relationship is:
This means that the force is a multiple of .
- Operating cylinderThe hydraulic pressure generated by the clutch master cylinder acts on the piston. It acts as a force that moves the piston. Also, together with the tension from the piston spring, it operates the clutch via the push rod and the release fork.The bore of the operating cylinder is larger than the bore of the master cylinder, which reduces the pedal force required when operating the clutch.
Piston spring
Push rod
Piston
From the master cylinder
2-6 2 Power Transmission System
[2] Checks and maintenance(1) Pedal stroke check 1. Measure stroke a of the clutch pedal. If the
value deviates from the standard, loosen the locknut and turn the adjust nut to adjust pedal
stroke a. 2. After adjustment, tighten the locknut to the
specified torque.
Adjust bolt
Locknut
Clutch pedal
a
3013
Clutch pedala
(2) Pedal allowance check 1. Measure distance a, which is the distance
until resistance is felt when the clutch pedal is pushed down.
(3) Clutch start systemThe clutch start system is a safety mechanism in MT vehicles that prevents mistaken start-off when
starting the engine. In this system, if the driver turns the ignition key to the engine start position without stepping on the clutch pedal, the clutch start switch in the engine start circuit does not supply power to the starting motor.
Clutch start switch
Clutch pedal
3P36
M
Main fuse
Ignition switch
Clutch start switch
Starter relay
Magnetic switch
Starting motor
STStarter fuse
3P51
Engine start circuit
2-72 Power Transmission System
2. I f the measured value deviates from the
standard, turn the adjust nut of the clutch cable
on the transmission side to adjust release arm
allowance b.
Clutch cable
Adjust nut
Release arm
3015
b
Clutch pedal
3016
a
3. After adjusting the release arm allowance,
check again allowance a of the clutch pedal, and start the engine to check whether the clutch operates normally.
(3) Checkofthepedalandfloorplate clearance when the clutch is disengaged
1. Start the engine. While the engine is idling, fully
pull up the parking brake lever and place wheel blocks around the tires.
2. S t e p o n t h e c l u t c h p e d a l a n d p u t t h e
transmission into the 1st gear.
3. Slowly release the clutch pedal so that the
vehicle does not start off suddenly. In the position immediately before the clutch engages, measure clearance a between the pedal and the floor plate.
(4) Clutch start system check 1. Check that the c lutch pedal s t roke and
allowance are within the standards, and adjust
them if there are any problems. 2. Check that the starting motor does not operate
when the clutch pedal is not stepped on. 3. Check that the starting motor does operate
when the clutch pedal is fully stepped on. 4. If there is a problem, check the clutch start
switch or perform adjustments.
(5) Clutch start switch check 1. Remove the connector from the clutch start switch.
Check that there is no conduction between the
connector terminals when the clutch pedal is not stepped on. Check that there is conduction between
the terminals when the clutch pedal is stepped on.
Clutch start switch
Clutch pedal not stepped on
Clutch pedal stepped on
Service wire
3P37
2. Measure clearance a between the threaded end
of the clutch switch and the pedal stay. If the value deviates from the standard, adjust by loosening
the locknut and turning the clutch start switch. 3. After adjustment, tighten the locknut to the specified torque.
Pedal stay Clutch start switch
Locknut
Threaded end 3P38
a
2-8 2 Power Transmission System
(6) Clutch discUse a slide gauge to measure the rivet sink. If the
value is equal to or lower than the limit, replace the clutch disc. Perform the measurements on both
sides of the clutch disc.
3017
Clutch disc
Rivet
Slide gauge
Clutch pedal
Bleeder plug
(7) Clutchfluidairbleeding1) Regular typePerform in the same way as air bleeding for the
brake hydraulic system, but also pay attention to the following.- During the air bleeding operation, make sure that
the fluid level does not drop to half or less.
- After bleeding the air, tighten the bleeder plug to the specified torque.
2) Special type (Swift: RS Series)If the clutch pedal feels soft when you step on it, air may have entered the hydraulic system. Follow the
procedure below to bleed the air.
3. Step on the clutch pedal several times and then
keep stepping down on it. While pushing the clamp, pull out the pipe connector by 1 notch.
When the hydraulic pressure stops, push in the pipe connector. (At this time, the clamp rises and the pipe connector locks.) Repeat this
operation until the air is eliminated from inside the clutch hydraulic system.
Operating cylinder
Operating cylinder
Plastic tube
Bleeder plug
Container
3P01
Clamp
Pipe connector
3P02
4. When the air is eliminated, keep stepping down on the clutch pedal. Push in the pipe connector
and check the locking of the clamp. 5. After finishing the air bleeding operation, step
on the clutch pedal and check that there are no fluid leaks.
6. Fill the reservoir tank with the specified brake
fluid up to the MAX level.
1. Fill the reservoir tank with brake fluid up to the
MAX level (the clutch and brakes share the
same reservoir tank).
(During the air bleeding operation, make sure
that the fluid level does not drop to half or less.)
2. Remove the bleeder plug cap, install one end
of the plastic tube onto the bleeder plug and insert the other end into a container.
2-92 Power Transmission System
(4) Sudden forward movement (jumping out)
Sudden forward movement is a symptom where the vehicle does not start off smoothly. The vehicle may jump forward automatically when the clutch pedal is
operated, or the engine may feel like it will stop.Check carefully whether the cause of the sudden
forward movement is insufficient smoothness in the operation mechanism, or uneven transmission torque caused by a defect in the clutch unit.To perform the check, start the engine, put the transmission into the 1st gear or reverse and slowly
connect the clutch. If the vehicle does not start off suddenly, you can conclude that the clutch unit is in a good condition.
(5) Abnormal noiseContinuous abnormal noise may be caused by
defects in the pilot bearing, release bearing or input bearing, or in bearings inside the transmission. While the vehicle is stopped and the engine is operating, if the abnormal noise stops when you step on the clutch pedal, the defect is probably in a bearing inside the transmission. If the abnormal noise does not stop at this time, the defect is probably in the release bearing or the pilot bearing. Sometimes, a temporary abnormal noise is made during acceleration or deceleration while the clutch is engaged. In such cases, depending on the noise type and the conditions under which it occurs, you must check not only the clutch and transmission, but also parts such as the engine mount and drive belt.
[3] Failure diagnosis(1) Engagement defectTo check for engagement defect, first put the transmission
into the 1st gear while stepping on the clutch pedal. Next,
put the transmission into the neutral position, step on the accelerator pedal to raise the engine rotation speed, and then return the transmission to the 1st gear. At this time,
continue stepping down on the clutch pedal. If an abnormal noise (gear noise) occurs during the above operations, you
can diagnose the problem as engagement defect.In the engagement defect check, you must determine whether the engagement defect occurs because the movement distance of the pressure plate is too short, or whether the engagement defect is caused by a clutch unit problem where the clutch disc cannot separate from the flywheel and pressure plate.
(2) SlippingIf slipping occurs between the clutch disc and pressure plate, it may impair the transmission of power from the engine to the transmission and cause acceleration problems. For this reason, be careful during diagnosis
because this problem is easy to mistake for an engine failure. Check carefully whether the origin of the problem
is in the operation mechanism or the clutch unit.Before performing the check, pull up the parking brake,
place wheel blocks around the tires and fully stop the vehicle. Then, step on the clutch pedal, put the transmission into the 4th gear, and slowly connect the clutch while slowly raising the engine rotation speed. If the engine stops at this time, the clutch is in a good condition. But if the engine does not stop and the vehicle does not
move forward, you can conclude that the clutch is slipping.
(3) Unsmooth engagementCheck carefully whether the cause is insufficient
smoothness in the operation mechanism, or uneven transmission torque caused by a defect in the clutch unit. Check carefully because this may also cause
the engine output to drop or other problems.To perform the check, start the engine, step on the clutch pedal, put the transmission into the 1st gear and slowly connect the clutch. If there is
no uncomfortable vibration at this time, you can conclude that the clutch unit is in a good condition.
2-10 2 Power Transmission System
2. Manual transmission1) OverviewWhen a vehicle starts off, a large driving force is required even though the engine rotation speed is low. But
when a vehicle is driven at high speed, a high engine rotation speed is required even though the driving force is low. The transmission enables the vehicle to meet these different requirements.A vehicle must also operate smoothly across many different driving conditions. For example, driving at high
speed or slow speed, climbing up or going down hills, repeatedly stopping and starting off, and reversing. The transmission converts engine rotation speed and engine torque in accordance with these driving conditions and transmits them to the drive wheels.
2) FunctionsThe transmission is a gear change mechanism. Its basic purpose is to transmit engine power to the propeller shaft and drive shaft. It has the following functions, which are essential for the operation of the vehicle.
- Power transmissionThe transmission transmits force by meshing gears together.
Main shaft or output shaft
- Reverse rotationA gear is added to change the rotation direction.
- Increasing torque and increasing engine rotation speedThe transmission changes the torque and speed by changing gear combinations to change the gear ratio.
Input shaftOutput shaft
Crankshaft or input shaft
Countershaf t ,
reverse gear
Increasing the force
(engine rotation speed drops)
Changing gears
Speed reduction
A small gear rotates a large gear
Speed increase
A large gear rotates a small gear
Increasing the engine rotation speed
(force drops)
Input shaft
Output shaft
Idle gear
2-112 Power Transmission System
- Power disconnectionThe transmission cuts off the power transmission by disconnecting the gear meshing.
Input shaftOutput shaft
Stop
2-12 2 Power Transmission System
Input shaft
HubSleeve (3-4)
Main shaft
Shift lever
Each speed change gear
Countershaft Gear
Sleeve (1-2)3019
3020
Countershaft 1st gear
Countershaft 2nd gear
Countershaft 3rd gear
Countershaft 4th gear
Input shaft 5th gearInput shaft 4th gear
Input shaft 3rd gearInput shaft 2nd gear
Reverse idler gear
Input shaft 1st gear
Countershaft 5th gear
(1) Gear change
[1] Structure and operationA vehicle requires a large driving force when starting off, and a high engine rotation speed when driving at high speed.To achieve this, the transmission varies the engine rotation speed and torque by changing the gear combinations (gear ratio).
The engine power is transmitted to the transmission input shaft via the clutch. The rotation of the input shaft is transmitted to the main shaft gear via the countershaft gears. Because the main shaft gear meshes to
the main shaft through the synchro-mechanism that is described later, the rotation from the countershaft is transmitted to the main shaft.In other words, the gear ratio is changed when the sleeve moves in accordance with the shift lever position and changes the gears on the main shaft that connect to the main shaft.When none of the gears on the main shaft mesh with the main shaft, the transmission is in the neutral condition. This means that when the vehicle is stopped and the engine is idling, the engine power rotates the input shaft, countershaft and the gears on the main shaft, but the main shaft does not rotate.
2-132 Power Transmission System
1st , 2nd and 3rd gear - Speed reduction (small
gear rotates a large gear)
4th gear - Direct connection (rotation is transmitted
unchanged)
5th gear - Speed increase (large gear rotates a small gear)
Reverse gear - Reverse rotation (gear is added)Increasing the force (engine rotation speed drops)
Speed reduction
Increasing the engine rotation speed (force drops)
Speed increase
Changing gears
3021
A small gear rotates a large gear
A large gear rotates a small gear
In the time that a large gear with 20 teeth
rotates once, a small gear with 10 teeth rotates
twice. In other words, the small gear rotates at twice the speed of the large gear, but transmits only half the force.
Input shaft Torque
Output shaft
Torque increase
3022
Tire rotation speed is reduced but torque is increased
In this way, the relationship between the transmitted torque and engine rotation speed is determined by the ratio of meshed gear teeth. This means that the torque and the engine rotation speed can be expressed as follows.Engine torque x gear ratio = output shaft torque
(2) Gear ratioThe gear ratio is the ratio between the input gear and output gear rotation speeds. The gear ratio changes as the transmission reduces or increases the engine rotation speed with different gear combinations.
For example, when the engine operates at a
constant torque and a constant speed, if the gear ratio is high (a small gear rotates a large gear), then
a high torque but a low engine rotation speed are transmitted to the tires.But if the gear ratio is low, a low torque and a high
engine rotation speed are transmitted to the tires.
2-14 2 Power Transmission System
Torque is determined by the size of the force that is applied and the distance from the point of support to the location where the force is applied.This means that when 2 different torque
wrenches, one long and one short, are used to generate the same torque, the longer wrench that is furthest away from the fulcrum requires less force than the shorter wrench.Torque (Nm {kgfcm}) =Applied force x
distance
1) Remote control typeIn remote control type, a rod or cable connects the shift lever to the transmission.This type minimizes vibration and noise because its use of anti-vibration rubber makes it difficult for
engine vibration to be transmitted.
Input shaftOutput shaft
Additional gear
3023
3116
Shift lever
Gear shift control shaft
Gear shift shaft
Joint
Transmission
Fulcrum
3024Rod type
Shift lever
Gear shift control cable
Gear selector control cableTransmission
3115Cable type
Shift lever
Shift fork
3025
Shift fork shaft for 5th and reverse gears
Shift fork shaft for 3rd and 4th gears
Shift fork shaft for 1st and 2nd gears
2) Direct shift typeIn direct shift type, the shift lever is directly connected to the transmission.Most FR vehicles use this system because it
delivers fast shift operations and feels good to operate.
(3) Shift leverThe shift lever can be move horizontally to select the gear row (select movement), and forward
and back to move the gears (shift movement).
These movements move the internal parts of the transmission to change gear.
A gear is added to reverse the direction of rotation.
2-152 Power Transmission System
(4) Transmission operation1) Gear changeThe movement of the shift lever is transmitted unchanged to the gear shift selector lever inside the transmission.When the gear shift selector lever moves in the vertical direction shown in the figure to select and
rotate a gear, it moves the synchro hub and meshes the gear with the main shaft.
2) What is the synchromesh mechanism?
The synchromesh mechanism selects the gear to mesh wi th the main shaf t by moving the synchronizer sleeve. When in neutral, the gears on the main shaft rotate at a speed that is a multiple of the teeth ratio (reduction ratio) of the gears that
oppose the rotation speed of the countershaft. This means that the main shaft (synchronizer hub)
rotation speed and the rotation speeds of the gears on the main shaft are different. When the gears are changed, the synchromesh mechanism absorbs this rotation difference to ensure a smooth change.
3) Synchromesh mechanism structure
Gear shift shaft
3026
Gear shift yoke
Gear shift arm
Synchronizer hub
GearGear
Shift fork
Gear shift shaft
Gear shift selector lever
Gear shift selector shaft
Gear shift control shaft
Gear shift selector lever
Synchronizer key
Synchronizer sleeveSynchronizer ring
Cone
Synchronizer spring
Synchronizer hub Groove
Cone
3117
Gear
Synchronizer
sleeve
Synchronizer spring
Synchronizer ring
Synchronizer key
Synchronizer hub
2-16 2 Power Transmission System
4) Synchromesh mechanism operation- 1st stage synchronization action 1. When the shift fork moves the synchronizer
sleeve (referred to as sleeve from now on),
the sleeve and the meshed key move together to the right.
2. The end of the key pushes the ring against the
cone. This frictional force transmits the rotation force of the sleeve to the gear.
3. At this time, the difference between the rotation
speeds of the ring and gear and the friction with the cone shifts the rotation direction of the gear just by the difference between the key
groove width and the key width. As such, when seen from above, the splines on the inside of the sleeve and the ends of the ring splines face each other in different positions as shown in Figure A.
Protrusion Sleeve
Ring
Gear
Key
Sleeve
Ring
Gear
Ring splineSleeve spline
Cone
Key
3028
Figure A
Sleeve
Ring
Gear
Sleeve
Ring
Gear
Strongly pushes without
going forward
Cone
Key
Spring
Sleeve
Ring
Gear
Sleeve
Ring
Gear
Forward
(Synchronization
completed)
Cone
Key
3030
- 3rd stage synchronization meshing 1. The sleeve and gear rotation speeds are
equalized, and the ring is freed in the rotation direction.
2. As shown in the figure, the splines on the inside
of the sleeve push away the ring splines and move smoothly to mesh with the gear splines.
3. If there is a rotation difference between the ring
or gear and the sleeve, the frictional force of the ring and the gear cone stops the forward movement of the sleeve. It only allows forward movement after synchronization is completed. However, when the synchronization action
(frictional force) is weak, there is a gear noise
when meshing with the gear and gear shifting is difficult.
- 2nd stage synchronization action 1. As the shift lever is moved, the force acting on
the sleeve overcomes the spring. The sleeve goes over the key protrusion and moves forward (moves to the right in the figure).
2. The splines on the inside of the sleeve and the
ring splines hit against each other. 3. The force applied to the sleeve is transmitted
via the splines that continue to hit and contact each other, and strongly pushes the ring into the gear cone. This frictional force performs a strong synchronization action.
2-172 Power Transmission System
6) IBS structureThe IBS is made up of a 5th speed synchronizer sleeve, 5th speed synchronizer hub, 5th speed synchronizer
lever, 5th speed synchronizer ring and input shaft 5th gear.
5th speed synchronizer sleeve
5th speed synchronizer hub
5th speed synchronizer lever
5th speed synchronizer ring
Input shaft 5th gear
3P03
5) What is IBS (input shaft brake system)?When shifting into reverse, even if you step on the clutch to cut off the power from the engine, inertial force continues to rotate the input shaft. This means that when shifting into reverse, the reverse gear of the input shaft that continues to rotate and the reverse idler gear that is stationary are not synchronized. This results in poor shifting into reverse gear and a gear noise. To minimize this effect, the IBS applies a brake to the
input shaft with the 5th speed synchronizer ring to reduce the rotation speed and ensure a smooth shift into reverse.
Input shaft Input shaft
Reverse gear
Reverse idler gear Reverse idler gear
Reverse gear
:Rotation :Brake
5th gear
IBS
3P46
2-18 2 Power Transmission System
7) IBS operation- When in neutralWhen the input shaft is rotating due to inertial force, the 5th speed synchronizer sleeve and 5th speed synchronizer lever also rotate. As such, the 5th speed synchronizer lever pushes out toward the circumference due to centrifugal force. This meshes the flange of the 5th speed synchronizer lever with the
groove of the 5th speed synchronizer sleeve.
Input shaft 5th gear
Mesh
Input shaft
:Input shaft rotation
:Centrifugal force
3P04
5th speed synchronizer lever
5th speed synchronizer lever
Groove of 5th speed synchronizer sleeve
Flange of 5th speed synchronizer lever
5th speed synchronizer sleeve
3P47
Input shaft 5th gear
Reverse idler gear
:Rotating area Differential assembly
Input shaft
Countershaft
Reverse gear5th speed synchronizer sleeve
5th speed synchronizer lever
2-192 Power Transmission System
- Start of synchronizationWhen shifting into reverse, the 5th gear shift fork moves the 5th speed synchronizer sleeve in the direction of arrow A. At this time, the 5th speed synchronizer lever moves the flange of the 5th speed synchronizer
lever in the direction of arrow B, with the 5th speed synchronizer hub as the fulcrum because the 5th speed
synchronizer hub is fixed to the input shaft. This means that the 5th speed synchronizer lever pushes the 5th
speed synchronizer ring, so that the 5th speed synchronizer ring and the cone surface of the input shaft 5th gear make contact. This applies a brake to the input shaft, reducing its speed. As such, it is easier for the reverse idler gear and the input shaft reverse gear to mesh, enabling a smooth shift into reverse.
3P48
Input shaft 5th gear
Reverse idler gear
Differential assembly
Input shaft
Countershaft
Reverse gear
5th speed synchronizer lever
5th speed synchronizer ring
5th speed synchronizer sleeve
Fulcrum
5th speed synchronizer ring
Cone surface
Input shaft 5th gear
Input shaft
:Input shaft rotation
:Shift fork movement
:Synchronizer lever pulling force
:Synchronizer ring pushing force
:5th gear cone surface pushing force
5th gear shift fork
Input shaft 5th gear
5th speed synchronizer ring
5th speed synchronizer sleeve
A
A
BB
B
B
B
3P05
5th speed synchronizer lever
5th speed synchronizer sleeve
Flange of 5th speed synchronizer lever
Flange of 5th speed synchronizer lever
5th speed synchronizer hub
5th speed synchronizer lever
5th speed synchronizer hub
2-20 2 Power Transmission System
- Gear change completionWhen the 5th speed synchronizer sleeve moves further in the direction of arrow A, the 5th speed synchronizer lever is pushed in the direction of arrow C. This eliminates the force of the 5th speed
synchronizer lever pushing against the 5th speed synchronizer ring. At this time, the 5th speed synchronizer ring and the cone surface of the input shaft 5th gear separate, which releases the brake that was applied to the input shaft. This means that after the gear change is completed, the input shaft can rotate again.
C
C
Input shaft
5th speed synchronizer lever
5th speed synchronizer hub
5th speed synchronizer ring
5th speed synchronizer sleeve
A
:Input shaft rotation
:Shift fork movement
:Synchronizer lever pulling force
5th speed synchronizer ring
A
C
C
Cone surface
5th speed synchronizer lever
5th speed synchronizer sleeve
Input shaft 5th gear
3P06
3P49
5th speed synchronizer sleeve
Input shaft 5th gear
Reverse idler gear
5th speed synchronizer lever
:Power transmission routeDifferential assembly
Input shaft
Countershaft
Reverse gear
2-212 Power Transmission System
Gear spline
ChamferSleeve splineSleeve
Tape
red
surf
ace
3031
(5) Mechanisms for safe drivingA manual transmission has various mechanisms for safe driving. These include a mechanism for preventing a meshed gear from jumping out while
driving, a mechanism for preventing more than one gear from meshing to the main shaft at the same time, and a mechanism for preventing the vehicle from being mistakenly put into reverse while driving.
1) Gear jump out prevention mechanismGear jump out is when a gear jumps out without a shift
operation. It often occurs because of changes in vibration or load while driving, such as during sudden acceleration or deceleration. If the gear jumps out, the transmission goes into neutral.
Gear jump out is often caused by gears meshing in a defective
way at the moment of shifting or by a shift in the positional relationship between the sleeve and gear while driving due to wear on the splines between the synchronizer sleeve and the gear resulting in an excessive thrust clearance.
- ChamferThe sleeve and gear spline fittings have tapered teeth surfaces.
During rotation, the gear spline is driven by the tapered surface,
which makes it difficult for the gear to jump out.
Spring
Detent ball
Shift fork shaft
Shift fork shaft
3032
- Detent ballThe detent ball is pushed into the ball groove on the shift fork shaft by the spring. This prevents gear jump
out and gives a good operating feel when shifting.
2) Reverse gear shift lever 1-way movement mechanism
In a manual transmission, the shift lever is operated to move the various shift fork shafts. The gear shift forks that are integrated with the shift fork shafts move to change the gears.In recent Suzuki vehicles, changing to reverse has been performed not by the sleeve movement, but by the movement of the reverse idler gear. Longitudinal manual transmissions use a reverse
gear shift lever 1-way movement mechanism. When
a shift operation is made that involves a movement in the direction of the 5th gear side and the reverse side of the 5th-reverse shift fork, the reverse gear shift lever 1-way movement mechanism is activated
only when the reverse gear shift lever is operated to one side (reverse side). This mechanism moves the
reverse idler gear.
- When in neutralWhen in neutral, because the pin of the 5th-reverse gear shift fork restricts the rotation of the reverse gear shift lever, the reverse idler gear does not move.
3P07
Reverse idler gear
5th-reverse gear shift fork
Groove of reverse gear shift lever
Pin of 5th-reverse gear shift fork
Reverse gear shift lever
2-22 2 Power Transmission System
3P08
Groove of reverse gear shift lever
Reverse idler gear
Reverse gear shift lever
Pin of 5th-reverse gear shift fork
5th-reverse gear shift fork
- ReversingWhen shifting from neutral to reverse, the pin of the 5th-reverse shift fork moves along the groove of the reverse gear shift lever, applying force to the reverse gear shift lever in the clockwise direction. The clockwise rotation of the reverse gear shift lever moves the reverse idler gear and fits it into the
input shaft.
3P09
Groove of reverse gear shift lever
Pin of 5th-reverse gear shift fork
Reverse gear shift lever
5th-reverse gear shift fork
Reverse idler gear
- When in the 5th speedWhen shifting from neutral to the 5th gear, the pin of the 5th-reverse gear shift fork moves inside the groove of the reverse gear shift lever, but because rotation force is not applied to the reverse gear shift lever, the reverse idler gear does not move.
- Transverse manual transmissionWhen shifting to 1st or 2nd gear, locking ball A that
is pushed out by the low speed shift shaft moves the pin and locking ball B. The balls enter the
grooves of the high speed shift shaft and the 5th shift shaft to regulate the movement of these shift shafts.
5th shift shaft
Transmission case
Locking
ball B
High speed shift shaft
Locking ball A
Pin
Low speed shift shaft
3) Double meshing prevention mechanism (interlock mechanism)
If 2 adjacent shift forks move at the same time,
there is a risk of 2 gears meshing.
To prevent this, a double meshing prevention mechanism (interlock mechanism) is used.
5th shift shaft
Locking
ball B
Transmission case
Low speed shift shaft
Pin
Locking ball A
High speed shift shaft
When shifting to 3rd or 4th gear, the high speed
shift shaft moves locking balls A and B, which enter
the grooves of the low speed shift shaft and the 5th shift shaft to regulate the movement in the shift direction.
When shifting to 5th or reverse gear, locking ball B
that is pushed out by the 5th shift shaft moves the pin and locking ball A. The balls enter the grooves of the low speed shift shaft and the high speed shift shaft to regulate the movement in the shift direction.
5th shift shaft
Locking
ball B
Transmission case
Low speed shift shaft
Pin
Locking ball A
High speed shift shaft
2-232 Power Transmission System
- Longitudinal manual transmissionThe lever of the gear shift selector arm and the lever of the gear shift interlock lever are always meshed in the yoke grooves.
Gear shift interlock lever
Yoke
Gear shift selector arm Lever of gear shift
interlock lever
Yoke
View from above Front view
Lever of gear shift selector arm
Lever of gear shift selector arm
Lever of gear shift interlock lever
Yoke
3P10
The lever of the gear shift selector arm can move in both the select direction and in the shift direction. However, the lever of the gear shift interlock lever can only move in the select direction.
Lever of gear shift interlock lever
Lever of gear shift selector arm
3P11
2-24 2 Power Transmission System
This means that only the yokes that are meshed with the lever of the gear shift selector arm can move in the shift direction. The movement of the yokes that are meshed with the lever of the gear shift interlock lever is restricted in the shift direction.
Gear shift interlock lever
Gear shift selector arm
Lever of gear shift interlock lever
Yoke
View from above Front view
Lever of gear shift selector arm
Lever of gear shift selector arm
Lever of gear shift interlock lever
Yoke
3P12
If the gear shift selector arm is shifted while it is in a middle position between Neutral and 1-2 or Neutral
and 5-R, the shift cannot be made because the yokes make contact with the lever of the gear shift interlock
lever.
Gear shift interlock lever
View from above Front view
Lever of gear shift selector arm
Lever of gear shift interlock lever
Yoke
Lever of gear shift interlock lever
YokeLever of gear shift selector arm
3P13
2-252 Power Transmission System
2. The 5th-reverse gear shift cam that shifts to
5th gear rotates, and the reaction force of the cam guide return spring moves the 5th-reverse interlock plate one step to the rear.
Cam guide return spring
5th-reverse gear shift cam
5th-reverse interlock plate
3037
3038Gear shift selector shaft
5th-reverse gear shift cam
5th-reverse interlock plate
Low select spring
5th-reverse interlock plate
3039
Gear shift selector shaft
Cam guide return spring
Gear shift guide case
Guide bolt5th-reverse interlock plate
Compressed
Compressed
Low select spring
3036 4. When the shift lever is returned to the neutral position, the reaction force of the low select spring returns the 5th-reverse interlock plate to its normal position, which allows shifting to reverse.
3. If shift ing to reverse is performed in this
condition, the gear shift selector shaft rotates, and the 5th-reverse gear shift cam continues to be pushed by the 5th-reverse interlock plate. This means that the shifting cannot be performed.
4) Inadvertent reverse operation prevention mechanism
An inadvertent reverse gear operation is when the gear jumps out from 5th gear, and through its own
momentum, enters the reverse gear.To prevent this, the mechanism is designed so that a shift to reverse gear cannot be made without first
returning the shift lever to neutral.
- Transverse manual transmission 1. When the shift lever is moved to the 5th gear,
the gear shift selector shaft is pushed in the gear shift guide case direction. At this time, the movement of the 5th-reverse interlock plate is regulated by the guide bolt, and the low select spring and the cam guide return spring are compressed.
2-26 2 Power Transmission System
- Longitudinal manual transmission 1. When the shift lever is moved to the 5th gear,
the gear shift selector arm that is integrated with the gear shift shaft rotates. At this time, because the lever of the gear shift selector arm pushes the ratchet cam, the ratchet compresses the ratchet spring and rotates.
Ratchet spring
Ratchet
Cam
Lever of gear shift
selector arm
3P14
2. When shift ing to 5th gear, the gear shift
selector arm slides, and the ratchet cam is freed from the pushing force of the lever of the gear shift selector arm. As a result, the reaction force of the ratchet spring returns the ratchet to its normal position.
Gear shift
selector arm
Ratchet spring
Ratchet
Lever
Cam
3P15
3. If the driver tries to shift straight from 5th gear
to reverse, the gear shift selector arm tries to slide. But because the lever and the ratchet
cam make contact with each other, the shifting cannot be performed.
4. When the shift lever is returned to the neutral position, because the movement of the gear shift selector arm is no longer restricted by the ratchet cam, the shift to reverse can be performed.
Gear shift
selector arm
Ratchet
Lever
Cam
3P16
Ratchet
Lever
Cam
Gear shift
selector arm
3P17
2-272 Power Transmission System
(6) Internal transmission lubrication
Oil lubrication inside the transmission is performed
with a gear that releases oil, and by supplying oil through the oil channels inside the shaft. This lubrication improves durability and reliability.
1) Input shaft internal lubricationOil that is released by the final gear runs into the
input oil gutter in the left case through centrifugal force. It is guided from the input oil gutter to the side cover, and then to the oil channel inside the input shaft through the oil pipe that is integrated with the side cover.The oil that is guided inside the input shaft flows from the oil holes in the 5th hub, 4th gear and high speed hub to lubricate the various parts.
2) Countershaft internal lubricationOil that is released by the final gear runs into the
oil pan of the right case bearing through centrifugal force. I t is gu ided to the o i l channel in the countershaft.The oil that is guided inside the countershaft flows
from the oil holes in the low speed hub and 2nd
gear to lubricate the various parts.
[2] Overhaul(1) Important points for disassemblyThere may be various reasons for disassembling the transmission, such as abnormal noise or stiff shifting.But before performing the disassembly, you must
first check for possible causes in locations other than the transmission unit. For example, if the shift
operation is stiff, if you disconnect the gear shift control cable on the transmission side and check the shift lever movement, you can judge whether or
not the cause is on the transmission side.With some transmission types, actual parts can be moved to identify the cause while only one side of the case is disconnected (before disassembling the transmission). These include the condition of the
gear backlash and gear meshing, the chattering of each shaft, and the smoothness of the rotation of each gear and shaft.Arrange the disassembled parts so that you remember to which system they belong. Be especially careful of
transmission internal parts, because many of these parts have a specific assembly direction. Make sure
that you remember the correct assembly method by taking notes or marking the parts.
(2) Check of internal transmission parts
1) Transmission case checkCheck mainly for cracks and that the breather plug
functions properly. If the plug is clogged, clean it.
2) Gear teeth surface checkCheck the gear teeth surfaces for excessive wear
or damage. If a gear is worn or damaged, replace it because it may cause abnormal noise.
3) Bearing checkClean the ball bearings and roller bearings and then
rotate them. Check that they operate smoothly and
do not catch. Also check the parts equivalent to the outer race and inner race in the taper roller bearing, and replace them as a set if there are any problems. Check the bushes for wear, streaks and cracks, and
replace them as a set if there are any problems.
Input oil gutterRight case
Left case3040
Side cover
Oil pipe
Input shaft
Countershaft
Right case bearing
Final gear
2-28 2 Power Transmission System
4) Synchromesh mechanism check 1. I f the clearance is equal to or below the
specified value when the synchronizer ring and
its partner gear are pushed together, replace the synchronizer ring. Also, if there is major
wear on the gear cone, replace as a set.
7) Check of parts in the interlock mechanism and gear jump out prevention mechanism
Check parts such as the interlock pin, spring and
locking balls, and replace if there are any problems such as damage, attenuation or wear.
(3) Important points for assemblyThe important points for assembly are to make sure that the correct parts are installed in the correct areas, in the correct direction and in the correct position. Information such as the allowance of each part before disassembly and the force required for operations must be noted down in advance. By performing this check in every stage, you
can prevent maintenance mistakes, such as discovering after reassembly that the gears are too stiff to shift.
[3] Failure diagnosisThe transmission is connected to the engine, and its rotation speed changes in proportion to the vehicle speed and together with the differential and tires. As such, if a problem occurs, the cause is not necessarily in the transmission. When performing failure diagnosis for the transmission, first the conditions and phenomena
under which the problems occur must be checked and the structure understood. The possible locations must then be narrowed down to find the cause.
(1) Abnormal noiseMost of the parts inside the transmission are sliding parts,
such as gears, bearings and the synchro-mechanism. If all parts in the transmission are covered by an oil film
they will not wear. But if wearing occurs, chattering will
occur in the sliding parts, resulting in abnormal noise. So in general, the conditions under which the abnormal noise occurs must be identified, and the operating parts
that are related to these conditions must be checked.Sometimes abnormal noise occurs only when driving with certain gears or only when shifting to certain gears. Under such conditions, the method described above
can be used to identify the problem. But if the problem
occurs across all driving ranges, the cause may be in many different locations, such as the differential, wheel hub, clutch, propeller shaft and drive shaft.
Clearance Gear
Cone
Synchronizer ring
3041
3118
Synchronizer sleeve
Gear shift fork
Slide gauge
2. Replace if there is significant wear on the
synchronizer key protrusion. Check for wear on
the synchronizer sleeve that covers the protrusion. 3. Replace if there is any breaking or attenuation
on the key spring.
5) Shift lever checkCheck for wear on the ball on the end of the shift
lever, and replace if there are any problems.
6) Shift fork checkMeasure the thickness of each shift fork claw and
the width of the synchronizer sleeve groove, and replace if their values deviate from the standard.
2-292 Power Transmission System
(2) Gear engagement and disengagement problems
Likely gear shift operation problems are (1) shift
lever to gear shift control cable, and (2) shift shaft
to shift fork to synchro-mechanism. When the transmission side of the gear shift control cable is disconnected and the shift lever is operated, if the movement is stiff, the problem is likely to be in system (1) above. If the movement is light, the
problem is likely to be in system (2).
During normal shift operation, the driver steps on
the clutch and the engine power is not transmitted to the transmission. For this reason, the same
problems occur if the clutch is not fully disengaged.
(3) Gear jump outGear jump out may occur more easily during a
sudden forward movement.Gear jump out may occur because of changes
in vibration or load after the gears meshed in a defective way at the moment of shifting. Or it may
occur because part wearing caused a shift in the positional relationship between the synchronizer sleeve and gear. To make a final identification of the
cause, the transmission must be disassembled.To check, shift to the gear that has the problem and make sure it is properly meshed. Repeatedly
perform sudden acceleration and deceleration to generate sudden forward movements, and check the gear jump out phenomenon. Also carefully
check the shift feeling (operation feel, weight) while
operating the shift.
(4) Oil leaksClean the location where you suspect there is an
oil leak. Perform a driving test and check the oil
leak location. Be aware that breather clogging and
overfilling may cause oil leaks.
2-30 2 Power Transmission System
4WD is an abbreviation of 4-wheel drive and
is used to describe 4-wheel drive vehicles.
Different drive systems include part-time 4WD
systems that can be switched between 2WD and
4WD; full-time 4WD systems that always drive
both the front and rear wheels; and real-time 4WD
systems that detect the driving conditions and automatically switch between 2WD and 4WD.
Di f fe rent fu l l - t ime 4WD sys tems inc lude a
rotary blade coupl ing (RBC) type and axia l
plunger pump coupling (AXC) type that limit the
differential mechanically with hydraulic pressure; a viscous coupling type that limits the differential through the viscous resistance of the silicone oil; a torque-sensitive cam type that limits the differential mechanically with frictional force; and an electromagnetic control device (EMCD) that
continuously switches between 2WD and 4WD
through electronic control based on the driving conditions.Note that full-time 4WD systems use a differential
that absorbs the rotation difference between the front axle and rear axle when turning.
3043Propeller shaft
Propeller shaft
Propeller shaft
Transfer
Transmission
Front wheel Rear wheel
The transfer may be separate from the transmission or it may be integrated with the transmission. It transmits the engine power to the front and rear wheels through a propeller shaft or drive shaft.
3. TransferWhen driving on uneven or slippery roads or climbing steep slopes is difficult for a 2-wheel drive
(2WD) vehicle where drive is supplied only to the
rear wheels or front wheels, the remaining tires are also used as drive wheels. 4-wheel drive (4WD)
vehicles have a mechanism for splitting the engine power between the rear wheels and the front wheels. This mechanism is called the transfer.
2-312 Power Transmission System
[1] Structure and operation(1) Part-time 4WD, separate from the transmission (Jimny: SN413)1) Part structureThe components in this type include an input shaft, drive chain, front output shaft, rear output shaft, counter gear and associated gears, hub, sleeve and shift shaft.The high-low clutch sleeve of the rear output shaft is used to switch between the low range and the high range. The sleeve on the front output shaft side is used to switch between 2WD and 4WD.
Input shaft
Counter gear
High-low clutch sleeve
Drive chain
Speed meter sensor ring
Rear output shaftOutput gear
T/F actuator2-4 shift fork
Front clutch hub
Front output shaft
Fixed shift shaft
T/F 4WD switch T/F L4 switch
Movable shift shaft
Front clutch sleeve High-low
shift fork
2-32 2 Power Transmission System
2) Operation- 2H positionThe driving force from the transmission is input to the input shaft and transmitted from the input shaft to the output gear via the drive chain. At this time, because the output gear and rear output shaft are fitted to each
other, the driving force is transmitted to the rear output shaft by the high-low clutch sleeve.Note that because the front clutch hub is not fitted to the front output shaft, the driving force is not transmitted
to the front output shaft.
Input shaft
Counter gear
Drive chain
Rear output shaft
Output gear
T/F actuator
Front output shaft
Front clutch hub
Front clutch sleeve
Fixed shift shaft
Movable shift shaft
T/F 4WD switch (OFF) T/F L4 switch (OFF)
High-low clutch sleeve
4WD/4L indicator (in the combination meter)
2-332 Power Transmission System
- 4H positionWhen the driver pushes the 4WD switch of the 2WD/4WD selector switch and shifts into the 4H position, the
motor of the T/F actuator rotates and the movable shift shaft shifts in the direction of arrow A. The pin that is
installed on the 2-4 shift fork fits into the groove of the movable shift shaft and moves the 2-4 shift fork in the
same direction as the movable shift shaft. As a result, the front clutch sleeve moves in the direction of arrow B.
In the same way as when in the 2H position, the driving force from the transmission is transmitted from the
input shaft to the rear output shaft via the drive chain. However, because the front clutch hub is fitted to the
front output shaft by the front clutch sleeve, the driving force is also transmitted to the front output shaft.
Input shaft
Counter gearDrive chain
Rear output shaft
Output gear
T/F actuator
Front clutch sleeve
Front clutch hub
2-4 shift forkFixed shift shaft
Movable shift shaft
T/F 4WD switch (ON)
Groove
Pin
T/F L4 switch (OFF)
High-low clutch sleeve
Front output shaft
4WD/4L indicator (in the combination meter)
2-34 2 Power Transmission System
- 4L positionWhen the driver pushes the 4WD-L switch of the 2WD/4WD selector switch and shifts into the 4L position,
the motor of the T/F actuator rotates and the movable shift shaft shifts in the direction of arrow A. At this time,
the snap ring that is installed on the movable shift shaft moves the high-low shift fork in the same direction as the movable shift shaft. As a result, the high-low clutch sleeve moves in the direction of arrow B.
The driving force from the transmission is input to the input shaft and transmitted to the output gear via the drive chain. At this time, because the output low gear and rear output shaft are fitted to each other by the
high-low clutch sleeve, the driving force is reduced with the output low gear via the counter gear, and is transmitted to the rear output shaft.In the same way as when in the 4H position, because the front clutch hub is fitted to the front output shaft by
the front clutch sleeve, the driving force from the rear output shaft is transmitted to the front output shaft.
Input shaft
Counter gear
Drive chain
Output gear
Rear output shaft
Output low gear
High-low shift fork
T/F actuator
Front clutch sleeve
Movable shift shaft
T/F 4WD switch (ON)
Snap ring
T/F L4 switch (ON)
High-low clutch sleeve
Front output shaft
4WD/4L indicator (in the combination meter)
Front clutch hub
2-352 Power Transmission System
(2) Full-time 4WD (Swift: RS413)1) Part structureThe components are an intermediate shaft, reduction drive gear, reduction driven gear, input bevel gear, output bevel pinion and flange.
2) OperationA The power transmitted from the front differential case is input to the reduction drive gear. The power is sent via the reduction driven gear to the input bevel gear, where its direction is changed by 90. It is
output to the output bevel pinion and transmitted to the propeller shaft.B The power transmitted from the front differential gear is input to the intermediate shaft. It passes
through the reduction drive gear and is transmitted to the right side drive shaft.
Reduction drive gear
Intermediate shaft
Left case
Right case
Reduction driven gear
Input bevel gear
Retainer shimSpacer
Output bevel pinion
Retainer
Flange
2-36 2 Power Transmission System
(3) Full-time 4WD (Grand Vitara: JB420)1) Part structureThe components in this type include an input gear, center LSD, front drive shaft, front drive chain, counter
gear, front output shaft, rear output shaft and associated gears, hub and sleeve. The center LSD is a torque-
sensitive cam type that has both a differential absorption function (differential function) and limited-slip
differential function (LSD function).
The drive modes are 4H (center LSD unlocked), 4HL (center LSD locked), 4LL (center LSD locked) and
neutral. Switching between these modes is performed by the T/F actuator, when the driver operates a
selection dial on the center console.
Input gear
High-low shift fork
Low gear
Front drive shaft
Transfer oil pipe
Counter gear
Front output shaft
Center LSD rear drive cam
Reduction shift sleeve
Center LSD case
Center LSD rear drive follower
Center LSD front drive cam
Differential lock shift fork
Differential lock clutch sleeve
Front drive sprocket bush
Front drive chain
Front drive sprocket
Rear output shaft
2-372 Power Transmission System
2) Operation- 4H position (center LSD unlocked)In this position, the reduction shift sleeve is fitted to the input gear and the center LSD case, and the
differential lock clutch sleeve is fitted to the front drive shaft and the front drive sprocket.
This means that the driving force from the transmission is transmitted to the rear output shaft and front output shaft via the route shown in the figure.
When the vehicle turns, a difference in rotation speed occurs between the input gear, rear output shaft and front output shaft. The drive follower in the center LSD moves in a reciprocating action between the drive
cams to absorb the difference in rotation speeds. When slip occurs at the front and rear wheels, frictional force between the drive follower and drive cam is generated from the difference in rotation of the front drive cam and the rear drive cam. This friction limits the slip differential for the drive cam on the side that is not slipping, transmitting the driving force to vehicle wheels.
Input gear
Reduction shift sleeve
Center LSD case
Front output shaft
:Rear side transmission route
:Front side transmission route
Differential lock clutch sleeve
Rear output shaft
Front drive chain
Front drive shaft
Front drive sprocket
3P39
Center LSD case
Drive follower Front drive cam
Rear drive cam
2-38 2 Power Transmission System
- 4HL position (center LSD locked)In this position, the reduction shift sleeve is fitted to the input gear and the center LSD case, and the
differential lock clutch sleeve is fitted to the front drive shaft, the front drive sprocket and the front drive
sprocket bush.This means that the driving force from the transmission is transmitted to the rear output shaft and front output shaft via the route shown in the figure.
Front output shaft
:Rear side transmission route
:Front side transmission route
Differential lock clutch sleeve
Input gear
Reduction shift sleeve
Center LSD case
Rear output shaft
Front drive chain
Front drive shaft
Front drive sprocket
3P40
2-392 Power Transmission System
- N positionIn this position, the reduction sleeve is fitted to the center LSD case only.
The driving force from the transmission is input to the input gear, but because the reduction sleeve is not fitted to the input gear, the driving force is not transmitted.
Front output shaft
:Rear side transmission route
:Front side transmission route
Front drive chain
Differential lock clutch sleeve
Rear output shaft
3P41
Input gear
Reduction shift sleeve
Center LSD case
2-40 2 Power Transmission System
- 4LL position (center LSD locked)In this position, the reduction shift sleeve is fitted to the low gear and center LSD case, and the differential
lock clutch sleeve is fitted to the front drive shaft, front drive sprocket and front drive sprocket bush.
This means that the driving force from the transmission is transmitted to the rear output shaft and front output shaft via the route shown in the figure.
Front output shaft
:Rear side transmission route
:Front side transmission route
Differential lock clutch sleeve
3P42
Input gear
Reduction shift sleeve
Low gear
Center LSD case
Rear output shaft
Front drive chain
Front drive shaft
Front drive sprocket
Front drive sprocket bush
2-412 Power Transmission System
When a part-time 4WD vehicle is driven in
4-wheel drive, the front and rear propeller shafts are connected and the rotation speeds of the front and rear axles are the same. For this
reason, when driving on a sharp curve on a dry, paved road, the difference in the turning radius between the front and rear wheels results in a rotation difference between the tires (drive shaft rotation difference). It feels like brakes
are being applied to the front wheels. The rear wheels feel like they are slipping. This is called the phenomenon of tight corner braking.To e l i m i n a t e t h e t i g h t c o r n e r b r a k i n g phenomenon, full-time 4WD vehicles have a
mechanism that absorbs the rotation difference. It is positioned in the area that transmits the driving force of the front and rear axles. This mechanism enables stable driving that is not affected by road conditions or the weather, allowing driving in 4-wheel drive at all times.
(4) Synchro-mechanism1) Double cone synchro-mechanism The components of the double cone synchro-mechanism are a front drive hub, front drive sleeve, synchronizer key, spring, outer ring, center cone and inner ring.
3054
Front drive hub
Synchronizer keyFront drive sleeve
Drive sprocket
Spring
Outer ring
Inner ring
Center cone
Synchronizer keyFront drive
sleeve
Spring
Front
drive
hub
Plate
Outer ring
Center cone
Inner ring
Drive
sprocket
3119
2-42 2 Power Transmission System
When the driver shifts the transfer lever from 2H to
4H, the front drive sleeve (referred to as sleeve
from now on) moves to the right. At this time, the
synchronizer key (referred to as key from now on) also moves to the right. The end of the key
makes contact with outer ring, and so the outer ring also moves to the right. As the outer ring moves further to the right, it makes contact with center cone surface A. As the center cone moves to the right, center cone surface B and the inner ring
make contact and generate frictional force. This frictional force rotates the outer ring as far as a position opposite to the spline chamfer surface. The sleeve and the outer ring make contact with each other through their chamfer surfaces, transmitting the operation force to the outer ring. This operation force generates an even greater frictional force between center cone surfaces A and B, which has
a synchronizing action that reduces the difference in rotation speeds between the sleeve and the drive sprocket.
The synchronization action continues until there is no difference in rotation speeds between the sleeve and the outer ring. As the sleeve is moved further to the right, the spline chamfer surface of the sleeve slides and moves the spline chamfer surface of the outer ring, and the sleeve and outer ring are fitted
together by their splines. As the sleeve is moved further to the right, the spline chamfer surfaces of the sleeve and drive sprocket make contact.
Front drive sleeve
Outer ring
Outer ring spline
Center cone surface A
Center cone surface B
Drive sprocket
Drive sprocket spline
Synchronizer key
Sleeve spline
3056
Chamfer surface
Front drive sleeve
Outer ring
Outer ring spline
Center cone surface A
Center cone surface B
Chamfer surface
Drive sprocket
Inner ring
Drive sprocket spline
Synchronizer key
Sleeve spline
3055
2-432 Power Transmission System
The synchronization action continues until there is no difference in rotation speeds between the sleeve and the drive sprocket. As the sleeve is moved further to the right, the spline chamfer surface of the sleeve slides and moves the spline chamfer surface of the drive sprocket, and the sleeve and drive sprocket are fitted together by their splines. This completes the synchronization.
[2] Checks and maintenanceIn the same way as for the transmission, there may be various reasons for disassembling the transfer, such as abnormal noise or stiff shift ing. The possible causes and the check methods are the same as for the transmission.
Front drive sleeve
Outer ring
Outer ring spline
Center cone surface A
Center cone surface B
Drive sprocket
Drive sprocket spline
Synchronizer key
Sleeve spline
3057
Synchro-mechanism parts (synchronization action parts)
Drive sprocket
3058
Front drive sleeve
Outer ring
Center cone
Inner ring
Synchronizer key
Power transmission route
2-44 2 Power Transmission System
(2) Constant velocity universal joint
A constant velocity universal joint is used on the
drive shaft in areas that transmit power with a large angle, such as a front-wheel drive vehicle and rear axle shaft in a rear-wheel drive independent suspension vehicle. The structure of a constant velocity universal joint is complex, but is designed
so that no rotation speed changes occur in the driving axle and driven axle. This means there are no variations in the rotation speed and torque of the driving axle and driven axle, enabling smooth power transmission.
- Barfieldjoint
The bar field joint components include an inner race
and outer race that have guide grooves, and steel balls inside these guide grooves and a ball gauge that holds these balls.When the 2 axles rotate while at an angle to each
other, the spherical surfaces of the outer race and inner race change the angle while sliding in the groove direction. The steel balls sandwiched between the races transmit the power while rolling inside the guide grooves. This mechanism that absorbs the changes in angle maintains the same rotation speed for the driving axle and driven axle. This means that the power is transmitted smoothly without any variations in the rotation speed and torque of the driven axle.
3065
Drive shaft
Constant velocity universal joint
Final gear differential
4. Drive shaftThe dr ive shaft is direct ly connected to the differential and is used for power transmission. It is frequently used in independent suspensions.
Drive shaft
3066
Inboard joint (sliding constant
velocity universal joint)
Outboard joint (fixed constant velocity
universal joint)
3067 Outer race
Outer race
Steel ballInner race
Ball gauge
[1] Structure and operation(1) Drive shaftBecause the drive shaft is subjected to impacts
from the road surface and to torque that is amplified
by the reduction action of the differential, its twisting strength and rigidity must be many times that of the propeller shaft. For this reason, it is a steel bar and
not hollow. To withstand these loads, the constant velocity universal joints on both shaft sides are also
made of strong material.In the same way as the propel ler shaft , the drive shaft has constant velocity universal joints
that can transmit rotation smoothly. A constant velocity universal joint is positioned on the sliding
mechanism that absorbs the changes in the length in the axial direction caused by the up-and-down movement of the tires while driving. Another constant velocity universal joint also accommodates
large changes in the angle when turning because the shaft length is short, or because of up-and-down tire movements.
2-452 Power Transmission System
- Triport jointThe triport joint components include a housing,
roller and spider.Its power transmission is the same as that of the bar field joint. But also, because it absorbs the
extension and contraction of the drive shaft caused by the up and down movement of the wheels, the roller can move along the housing groove in the axial direction.
[2] Checks and maintenance(1) Drive shaftBe careful of the following when disassembling the
drive shaft.- In the same way as for the propeller shaft, draw
reference marks on the parts.- Before removing the boot, wrap the end of the drive
shaft with tape to protect it from damage.
3068Housing
RollerSpider
Boot
3070
Boot
Tape
Drive shaft
- Assemble the boot band for the resin boot as shown in the figure relative to the rotation direction of the drive shaft when going forward. Properly mesh the protrusions with the grooves (3
locations).
ProtrusionGroove
Rotation direction
3P27
- Assemble the boot band for the rubber boot as shown in the figure relative to the rotation direction
of the drive shaft when going forward.
Rotation direction
3P28
When filling the boot with grease, be sure to fill to
the specified level. If the specified level is exceeded
it will cause grease leaks, while if the level is insufficient, the joint may seize.
2-46 2 Power Transmission System
3069
Open the bellows-shaped area of the boot and
check al l around it that there are no cracks. Replace the boot if it is torn, but if there is abnormal
noise, replace the boot by replacing the drive shaft assembly.
(2) Constant velocity universal joint
Move the joint up and down and to the left and right,
and check that the operation is smooth and that there is no significant rattling. Check that the parts
that move in the axial direction do not catch and operate smoothly.
2-472 Power Transmission System
5. Propeller shaftA propeller shaft transmits power from the transmission to the front or rear axle. It is used in FR vehicles and
4WD vehicles.
Universal joints are installed on both ends of a propeller shaft or drive shaft. Even if the installation angle of
the shaft changes, these joints make the shaft rotate smoothly for power transmission.
Propeller shaft
Rear propeller shaft
Front propeller shaft
Drive shaft
Front
Front
Universal joint
Transmission side
Universal joint
Differential side
2-48 2 Power Transmission System
[1] Structure and operation(1) Propeller shaftTo transmit the powerful force from the engine, the propeller shaft is made from a steel pipe that is lightweight with high twisting strength and bending rigidity, and which has excellent properties for high speed rotation.The installation position of the propeller shaft that connects the transmission and the differential is not level, but is rather at a certain angle. When driving on bumpy roads, the installation position changes through various different directions. In accordance with these angle and installation position changes, the propeller shaft extends, contracts and tilts. This makes the rotation smooth and transmits the power to the final gear.
The figure below shows the components of the propeller shaft. They include the universal joints that
respond to the angle changes, and the sleeve yoke and propeller shaft unit that respond to changes in length in the axial direction. On this shaft, balance
pieces are installed at the time of production to balance the shaft for rotation (prevent vibration and abnormal noise).
Sleeve yoke
Spider
Propeller shaft
Balance pieceUniversal
jointUniversal
joint
Needlebearing
3072
3073
Differential
Radial ball bearing
Propeller shaftTransmission
Center bearing
Rubber bush
(2) Center bearingIn high-performance vehicles or large vehicles where there is a long distance from the transmission to the driving axle, the propeller shaft is split into 2 or 3 shafts
to raise its critical rotation speed. An area near the rear end of each shaft is supported with a radial ball bearing. This bearing is called the center bearing, and it is installed via a rubber bush to prevent the transmission of vibration to the vehicle body during rotation.
Critical rotation speedBecause the propeller shaft rotates at a high
speed while receiving ever-changing engine torque, twisting vibration is easily generated. Also, the propeller shaft may bend, and if the weight is not balanced, then bending vibration may occur. If these vibrations and the natural frequencies of the propeller shaft match, it will damage the propeller shaft. This rotation speed is called the critical rotation speed.The critical rotation speed can be calculated with the equation below. The longer the shaft length, the lower the critical rotation speed.
d22d12
n :Critical rotation speed (rpm) l :Shaft length (mm) d2 :Shaft outside diameter (mm) d1 :Shaft bore (mm)
*When the propeller shaft is a hollow steel pipe
2-492 Power Transmission System
(3) Universal jointA hook joint is often used as the universal joint. A
hook joints components include 2 yokes (input side
and output side), a spider (cross-shaped axle) that
connects these yokes, and a needle roller bearing.
[2] Checks and maintenance(1) Propeller shaft checkCheck the bending of the propeller shaft if it was
subjected to an impact, such as in an accident.
Check the bending by placing the propeller shaft
on a V block and setting a dial gauge on its center.
Gently rotate the shaft and measure.3074
Bearing race
Needle roller bearing
Oil seal
Oil seal retainer
Yoke
Spider
Propeller shaft
Flange yoke
3075
Yoke
Yoke
3076
V block
Propellershaft
Dialgauge
3077
The bend amount is half the dial gauge reading (deflection). Before performing the measurement,
remove the shaft paint from the areas that will contact the V block and the dial gauge. If the bend
exceeds the specified value, replace the propeller
shaft.
(2) Universal joint checkIf the propeller shaft rattles, check for joint wear.
If there are any problems, replace the propeller shaft by replacing the assembly. The rattling rhythm of the abnormal noise from the propeller shaft is proportionate to the driving speed. It tends to be particularly loud when starting off from a stop and during deceleration (when the engine brake effect is transmitted to the drive system).
The universal joints advantages is that its structure
is simple and wearing is low. The disadvantage is that when the driving axle and driven axle rotate at a certain angle to each other, the driven axles rotation speed and the torque vary relative to the driving axle. To absorb these variations, the direction (phase) of the yokes that are connected
to the universal joint are made the same. This
counteracts the rotation speed variations that are generated in the propeller shaft, achieving smooth power transmission. However, if the angle of the
driven axle relative to the driving axle becomes too large, even when the direction of the yokes that are connected to the universal joint are made
the same, the rotation speed variations cannot be counteracted. For this reason, a universal joint is
only used for parts such as the propeller shaft that have relatively small angle variations.
2-50 2 Power Transmission System
(3) Important points for propeller shaft disassembly (Jimny: SN413)
1. Before removing the propeller shaft, draw
reference marks on the joint and flange. This
will make sure that you assemble the parts in the same position and maintain their balance.
(4) Important points for propeller shaft assembly (Jimny: SN413)
1. Be sure to apply grease to the spider bearing
race, and check that the entire roller on the inner side of the spider bearing race is within the home position.
Flange
Reference mark
Joint
3 - 4 mm
Special tool
Copper hammer
Metal plate
Spider
Bearing race
Yoke
3083
Bearing
Spider
Bearing
Grease
3. Insert the bearing race on the yoke side, and
hit the bearing race with a copper hammer until it is in the same plane as the outer side of the yoke. Insert the spider into the bearing race while making sure that the bearing race roller does not come apart.
When hitting the bearing race, place a metal plate over the bearing race to prevent damage to the yoke.
2. Use a new snap ring, spider and bearing for
assembly.
3. Hit the yoke with a plastic hammer to fully
remove it from the bearing race.
2. Use a special tool to push out the universal
joint about 3 to 4 mm from the flange yoke.
Before pushing out the joint, apply a permeable
lubricant between the bearing race and yoke race.
2-512 Power Transmission System
4. In the same way, insert the bearing race on the opposite side into the yoke, and hit the bearing race with a copper hammer until it is in the same plane as the outer side of the yoke.
Copper hammer
5. After assembly, check that both the shaft yoke and flange yoke move together smoothly.
6. C