TA19 and TA22 Transmissions Power Train Electronic Control System Caterpillar

Transmission Clutch Engagement

Illustration 1	g01343698
Modulating Valves (Transmission Control Valves)

Each transmission control valve has a designated letter, as shown. The letters have been cast into the transmission housing.

Each transmission control valve controls an individual clutch. Each letter is assigned to a corresponding transmission control valve. See Illustration 1.

These letters are used in Table 2 to show the clutches that are engaged for each gear.

No more than two clutches are ever engaged at a time. Also, no more than one clutch is ever engaged on a shaft.

Problem List

The following problems are covered in this story:

• "The Tractor Does Not Move in Any Gear"

• "The Transmission Does Not Shift Into All of the Gears"

• "A Warning Event for Replacing the Transmission Oil Filters is Displayed in (Cat ET)"

• "The Transmission Shifts Too Hard"

• "A Warning Event for Low Transmission Oil Pressure is Displayed on the (Cat ET)"

• "A Warning Event for Elevated Transmission Oil Temperature is Displayed on the (Cat ET)"

• "The Transmission Locks Into One Gear"

• "The Transmission Slips"

• "Inching Control Does Not Work Properly"

The Tractor Does Not Move in Any Gear

1. Check the Caterpillar Electronic Technician (Cat ET) for diagnostic codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Check the sump for the correct type of oil and check the sump for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Perform the calibration procedure for the transmission clutches.

   Reference: Refer to Testing and Adjusting, "Transmission Clutch Calibration" for additional information.

4. Repair any problems that are found in the calibration procedure.

   Note: Operate the tractor. If the transmission does not function properly, continue with Step 5.

5. Perform the pressure tests for the transmission.

   Reference: Refer to Systems Operation/Testing and Adjusting for additional information.

6. Repair any failed components that are found while you perform the pressure tests.

The Transmission Does Not Shift Into All of the Gears

1. Check for diagnostic codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Check the reservoir for the correct type of oil and check the reservoir for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Perform the calibration procedure for the transmission clutches.

   Reference: Refer to Testing and Adjusting, "Transmission Clutch Calibration" for additional information.

4. Repair any failed components or replace any failed components that are found during the calibration procedure.

   Note: Operate the tractor. If the transmission does not function properly, continue with Step 5.

5. Perform the pressure tests for the transmission.

   Reference: Refer to Testing and Adjusting for additional information.

6. Repair any failed components or replace any failed components that are found during the pressure tests.

7. If a specific gear is missing, identify the clutches that are used for that gear. See Table 2.

8. Look for a gear that uses similar clutches.

9. Use a known working transmission control valve to replace the suspect transmission control valve. For example, if fourth gear (reverse) is working then you can use either transmission control valve (A) or (J) as a working transmission control valve. This will isolate the faulty solenoid valve. Replace any faulty solenoid valves that are found during the test.

A Warning Event for Replacing the Transmission Oil Filters is Displayed in (Cat ET)

1. Replace the hydraulic oil filters.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

2. Check for diagnostic trouble codes.

   Reference: See the appropriate stories in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

The Transmission Shifts Too Hard

1. Check for diagnostic codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Check the reservoir for the correct type of oil and check the reservoir for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Perform the calibration procedure for the transmission clutches.

   Reference: Refer to Testing and Adjusting, "Transmission Clutch Calibration" for additional information.

4. Repair any problems that are found in the calibration procedure.

   Note: Operate the tractor. If the transmission does not function properly, continue with Step 5.

5. Perform the pressure tests for the transmission.

   Reference: Refer to Testing and Adjusting for additional information.

6. Repair any failed components or replace any failed components that are found during the pressure tests.

7. If a specific gear is missing, identify the clutches that are used for that gear. See Table 2.

8. Look for a gear that uses similar clutches.

9. Use a known working transmission control valve to replace the suspect transmission control valve. For example, if fourth gear (reverse) is working then you can use either transmission control valve (A) or (J) as a working transmission control valve. This will isolate the faulty solenoid valve. Replace any faulty solenoid valves that are found during the test.

A Warning Event for Low Transmission Oil Pressure is Displayed on the (Cat ET)

1. Check for diagnostic trouble codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

   Note: Operate the tractor. If a warning event for low transmission oil pressure is still on, continue with Step 2.

2. Check the reservoir for the correct type of oil and check the reservoir for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Perform the pressure tests for the transmission.

   Reference: Refer to Testing and Adjusting for additional information.

A Warning Event for Elevated Transmission Oil Temperature is Displayed on the (Cat ET)

1. Check for diagnostic trouble codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Check the reservoir for the correct type of oil and check the reservoir for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Check the hydraulic oil cooler.

   1. Check the cooler for dirt or foreign material. Clean the cooler, if necessary.

      Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

   2. Check the cooler for damage. As required, repair components or replace components.

   3. Check the cooler lines for damage. As required, repair components or replace components.

4. Air flow across the cooler is low.

   1. Check the fan for damage. If the fan is damaged, replace the fan.

   2. Check the fan drive belt. The speed of the fan may be reduced if the fan drive belt is loose or if the fan drive belt is damaged. If the fan drive belt is damaged, replace the belt.

      Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

5. There appears to be air in the transmission oil.

   1. Find the location of the entry of the air into the system.

   2. As required, repair components or replace components.

The Transmission Locks Into One Gear

1. Check the (Cat ET) for any diagnostic code that is displayed.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Find the gear that is locked. Find the clutches that are used to engage the gear that is locked. See Table 2.

3. Perform the pressure tests for the transmission.

   Reference: Refer to Systems Operation/Testing and Adjusting, KENR5260 for additional information.

The Transmission Slips

1. Check for diagnostic trouble codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Check the reservoir for the correct type of oil and check the reservoir for the correct quantity of oil.

   Reference: Refer to the Operation and Maintenance Manual, SEBU8204 for additional information.

3. Perform the calibration procedure for the transmission clutches.

   Reference: Refer to Testing and Adjusting, "Transmission Clutch Calibration" for additional information.

4. Repair any problems that are found in the calibration procedure.

5. Perform the pressure tests for the transmission.

   Reference: Refer to Testing and Adjusting for additional information.

6. Repair any problems that are found during the pressure tests.

7. If the pressure is correct, the clutches may be worn. As required, repair components or replace components.

Inching Control Does Not Work Properly

1. Check for diagnostic trouble codes.

   Reference: See the appropriate sections in this manual that relate to the diagnostic codes. Repair any suspect components, as required.

2. Perform the calibration procedure for the transmission clutches.

   Reference: Refer to Testing and Adjusting, "Transmission Clutch Calibration" for additional information.