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1TCL017 Engineering Drawings

CX31 CAT TRANSMISSION

2TCL017 Engineering Drawings

• New Cat Product• 6 speed• Planetary gear• Powershift transmission• Compatible with C9-C15 Cat Engine• Torqon with lock up & free wheel stator• Optional retarder

Introduction

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3TCL017 Engineering Drawings

• Electronic Clutch Pressure Control (ECPC)• Separate transmission ECM• Gear type hydraulic pump

Introduction

4TCL017 Engineering Drawings

• Transmission control group at cab• R – Reverse• N – Neutral• D – Drive• Autoshift in 1st – 6th gear• ↑↓ - select max up shift speed

Introduction

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5TCL017 Engineering Drawings

Major Component

2. Transmission oil filter7. Pressure taps for main relief valve and

torque converter outlet pressures

6TCL017 Engineering Drawings

Major Component1. Magnetic screen3. Relief valve group4. Oil filter bypass valve5. Transmission main relief valve6. Torqon outlet relief valve

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7TCL017 Engineering Drawings

1. Cover2. Cover3. Hydraulic Pump4. Transmission ECM

Major Component

8TCL017 Engineering Drawings

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9TCL017 Engineering Drawings

Speed Vs Clutches Engaged

Neutral 5Reverse 3 and 51st Forward 1 and 52nd Forward 1 and 43rd Forward 1 and 34th Forward 1 and 25th Forward 2 and 36th Forward 2 and 4

10TCL017 Engineering Drawings

Torque Converter

• Inlet housing & Impeller (1)• Turbine & Output Shaft (2)• Freewheel stator 3)

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11TCL017 Engineering Drawings

12TCL017 Engineering Drawings

Relief valve group

1. Main relief valve 2400 kPa (350 psi)

2. Torque converter outlet relief valve ≅500 kPa (70 psi)

3. Torque converter inlet relief valve

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13TCL017 Engineering Drawings

14TCL017 Engineering Drawings

Transmission ECM function to determine the desired transmission gear and to energize the appropriate solenoids to shift the transmission up or down as required based on information from both the driver and truck

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15TCL017 Engineering Drawings

Transmission ECM provides diagnostic capabilities, stored in onboard memory. Technicians should use the Caterpillar

Electronic Technician (Cat ET) for troubleshooting

16TCL017 Engineering Drawings

Transmission calibration is performed automatically on the CX31 and CX35 transmissions. It is not necessary to manually calibrate the transmission

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17TCL017 Engineering Drawings

Transmission push button shift pad

• Mode switch (1) : Economy mode or standart mode

• Arrow keys (2) to limit the maximum transmission upshift speed

• LCD screen (3) displays the status of the transmission

18TCL017 Engineering Drawings

Transmission push button shift pad

• The left digit displays the maximum available gear

• The right digit displays the actual gear

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19TCL017 Engineering Drawings

Transmission electronic control component

• Transmission ECM (1).• Engine input speed

sensor (2)• Output speed sensors (3)• Solenoid valve (4)• Lock up solenoid valve

(5)• Filter bypass pressure

sensor (6)• Torque converter output

shaft speed sensor (7)

20TCL017 Engineering Drawings

Transmission electronic control component

• Torque converter oil temperature sensor (1)

• Transmission filter bypass switch (2)

• Transmission oil level sensor (3)

• Transmission oil temperature sensor (4)

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21TCL017 Engineering Drawings

22TCL017 Engineering Drawings

ECPC system operation

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23TCL017 Engineering Drawings

ECPC system operation

24TCL017 Engineering Drawings

ECPC system operation

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25TCL017 Engineering Drawings

Transmission Pressure Check

• Main relief pressure tap (1)

26TCL017 Engineering Drawings

Transmission Pressure Check• Cap (2)• The torque converter

outlet relief valve pressure tap (3)

• Cap (4)• Cooler inlet pressure tap

(5)• Torque converter inlet

pressure tap (6)

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27TCL017 Engineering Drawings

Transmission Test Port Location1. TC outlet temp (ET)2. Filter inlet pressure3. Main relief pressure4. TC inlet pressure5. TC outlet pressure6. Cooler inlet pressure7. Lube pressure location8. Lockup Clutch9. Clutch 1 ECPC10. Clutch 2 ECPC11. Clutch 3 ECPC12. Clutch 4 ECPC13. Clutch 5 ECPC

28TCL017 Engineering Drawings

rpmrpmrpmPort Location

13. Clutch 5 ECPC

12. Clutch 4 ECPC

11. Clutch 3 ECPC

10. Clutch 2 ECPC

9. Clutch 1 ECPC

8. Lockup Clutch

2140 – 138 kPa(310 – 20 psi)

7. Lube pressure location

6. Cooler inlet pressure

275 kPa(40 psi)

5. TC outlet pressure

1034 kPa(150 psi)

4. TC inlet pressure

2415 kPa(330 psi)

3. Main relief pressure

2140 – 138 kPa(310 – 20 psi)

2. Filter inlet pressure

1. TC outlet temp (ET)

2100Actual

1400Actual

600Actual

2100Actual

1400Actual

600Actual

Spec2100Actual

1400Actual

600Actual

90C+ (194F+) sump80C (176F) sump50C (122F) sump

CX31 Transmission Test Chart

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29TCL017 Engineering Drawings

30TCL017 Engineering Drawings

Always use the latest service information to ensure that the most current specifications

and test procedures are used

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31TCL017 Engineering Drawings

PREVENTIVE MAINTENANCE

32TCL017 Engineering Drawings

Transmission Oil

The CX Series of on-highway transmissions are designed to operate with ATF fluids that meet

Caterpillar AT-1 or Dexron® IIIH specifications. Cat ATF-HD, a new automatic transmission fluid

This fluid has been tested and approved by Caterpillar for use with the Cat® CX28,

CX31 and CX35 transmissions

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33TCL017 Engineering Drawings

Transmission Oil Capacities (Refill)

27 L (7 US gal)49 L (13 US gal)CX31 with Retarder

25 L (6.5 US gal)45 L (12 US gal)CX31 Standard Sump

20 L (5.3 US gal)38 L (10 US gal)CX31 Shallow Sump

Service RefillEstimated Initial FillTransmission Type

34TCL017 Engineering Drawings

Daily

• Transmission Oil Level - Check

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35TCL017 Engineering Drawings

Initial 200 Hours/8000 Km/5000 Miles

• Oil Filter (Transmission) - Replace

36TCL017 Engineering Drawings

500 Hours / 6 Months / 20 000 Km / 12 000 Miles

• Magnetic Screen (Transmission) - Clean • Oil Filter (Transmission) – Replace• Transmission Oil - Change • Transmission Oil Sample - Obtain

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37TCL017 Engineering Drawings

1000 Hours /1 Year / 40 000 Km / 25 000 Miles

• Magnetic Screen (Transmission) – Clean• Oil Filter (Transmission) – Replace• Transmission Oil - Change • Transmission Oil Sample - Obtain

38TCL017 Engineering Drawings

2000 Hours / 2 Years / 80 000 Km /50 000 Miles in General Applications

• Oil Filter (Transmission) – Replace• Transmission Oil Sample - Obtain

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39TCL017 Engineering Drawings

2000 Hours / 2 Years / 80 000 Km / 50 000 Miles in Severe Applications

• Magnetic Screen (Transmission) - Clean • Oil Filter (Transmission) - Replace • Transmission Oil - Change • Transmission Oil Sample - Obtain

40TCL017 Engineering Drawings

3000 Hours / 3 Years / 120 000 Km / 75 000 Miles in General Applications

• Oil Filter (Transmission) – Replace• Transmission Oil Sample - Obtain

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41TCL017 Engineering Drawings

3000 Service Hours or 3 Years or 120 000 Kilometers (75 000 Miles) in Severe

Applications• Magnetic Screen (Transmission) - Clean • Oil Filter (Transmission) – Replace• Transmission Oil - Change • Transmission Oil Sample - Obtain

42TCL017 Engineering Drawings

4000 Hours / 4 Years / 240 000 Km / 50 000 Miles in General Applications

• Magnetic Screen (Transmission) - Clean • Oil Filter (Transmission) – Replace• Transmission Oil - Change • Transmission Oil Sample - Obtain

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43TCL017 Engineering Drawings

Transmission Oil Level - Check

• Warmed to operating temperature• Engine LOW IDLE• Transmission NEUTRAL• Vehicle in level ground• Check level at dipstick in filler tube

(#1)

44TCL017 Engineering Drawings

Oil Filter (Transmission) - Replace

• Remove filter drain plug (3), drain• Install drain plug, tighten 18 ± 3.5

Nm (13 ± 3 lb ft)• Remove oil filter housing (1)• Discard the used oil filter element• Inspect the seal in the housing• Install the new oil filter element • Install housing (2) & the new

element into filter base (1)• Tighten 55 ± 5 N·m (41 ± 4 lb ft)

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45TCL017 Engineering Drawings

Magnetic Screen (Transmission) - Clean

• Remove drain plug (1)• Install, torque 35 ± 10 N·m

(26 ± 7 lb ft)

46TCL017 Engineering Drawings

Magnetic Screen (Transmission) - Clean

• Remove 3 bolts for access plate (2)

• Remove suction screen & magnetic filter inside

• Inspect & Clean, use stiff bristle brush

• Install magnetic filter, suction screen

• Install access plate, tighten 28 ±7 N·m (21 ± 5 lb ft)

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47TCL017 Engineering Drawings

Transmission Oil - Change

• Perform magnetic screen cleaning procedure

• Fill transmission case with oil through filler tube, refer to refill capacity

• Vehicle on level ground• Transmission is in NEUTRAL• Engine at LOW IDLE • Check oil level on dipstick

48TCL017 Engineering Drawings

Transmission Oil Sample - Obtain

• Run engine until reach operating temperature

• Take oil sample from sampling valve (1)

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49TCL017 Engineering Drawings