TH48-E80 Petroleum Transmission Caterpillar


Maximum Pressure for Lockup Clutch and Solenoid Valve (Torque Converter) - Test

Usage:

TH48-E80 FRT
Note: Transmissions FRT1-1198 have modulating reducing style lock up clutch valves, refer to Illustration 1. Transmissions FRT1199-Up have electronic clutch pressure control "ECPC" style valves, refer to Illustration 2. Modulating reducing style and ECPC style lock up clutch valves require software with different application codes. Refer to Special Instruction, REHS4541, "Software Configuration Guide{3168, 4800, 4808, 7600, 7610, 7620}".

Table 1
Required Tools 
Part Number  Description  Quantity 
198-4240  Digital Pressure Indicator 

Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before you perform this test.

Note: This procedure works for ICM and ECPC type LUC valves.

------ WARNING! ------

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine or release of air pressure or oil pressure can cause injury to persons on or near the machine.

To help prevent possible injury before testing and adjusting any air system or hydraulic system, perform the procedure in the Testing and Adjusting, "General Information" section.


This test will show the following conditions if the conditions exist:

  • The maximum lockup pressure is correct.

  • The operation of the modulation reduction valve is correct.

Procedure



    Illustration 1g01225624
    Pressure tap for the 312-4306 Lockup Clutch Valve effective on FRT00001-FRT01198.


    Illustration 2g03105877
    367-9108 Lockup Clutch Valve and Mounting Gp effective on FRT01199-.
    (1) Pressure tap

  1. Connect 198-4240 Digital Pressure Indicator to the nipple at the pressure tap for the lockup clutch pressure.

  2. Start the engine. Run the engine at the low idle rpm with the transmission in NEUTRAL. The pressure on the gauge must be 0 kPa (0 psi).

  3. Shift to FIRST gear and increase engine speed to 1900 rpm so the lock up clutch engages. The lock up clutch pressure must be 2206 ± 207 kPa (320 ± 30 psi).

  4. Disconnect the harness from the lockup clutch solenoid. The pressure on the gauge must be 0 kPa (0 psi).

  5. Stop the engine. After the pressure is correctly set, remove the test equipment.


Illustration 3g01726694
Lockup clutch valve effective on FRT00001-FRT01198
(1) Cover
(2) Selector piston
(3) Load piston
(4) Load piston plug
(5) Shims
(6) Inner spring
(7) Outer spring
(8) Load piston orifice
(9) Spool spring

Problem: The oil pressure is not 0 kPa (0 psi) when the lockup clutch solenoid is deactivated.

Probable Cause

  • Selector piston (2) is stuck.

  • Outer spring (7) is weak or broken.

  • The lockup clutch solenoid is bad. Perform the Testing and Adjusting, "Solenoid Valve - Test".

Problem: The oil pressure is 0 kPa (0 psi) with the lockup clutch solenoid activated.

Probable Cause

  • There is either a small amount of pilot oil or no pilot oil. Perform the test in the Testing and Adjusting, "Primary Pressure for Lockup Clutch and Solenoid Valve (Torque Converter) - Test and Adjust".

  • Outer spring (7) is weak or broken and/or inner spring (6) is weak or broken.

Note: Modulating reducing style and ECPC style lock up clutch valves require software with different application codes. Refer to Special Instruction, REHS4541, "Software Configuration Guide{3168, 4800, 4808, 7600, 7610, 7620}".

Problem: The oil pressure is too low with the lockup clutch solenoid activated.

Probable Cause

  • Load piston plug (4) is not installed.

  • Load piston orifice (8) is plugged.

  • Load piston (3) is stuck, and/or selector piston (2) is stuck.

  • Outer spring (7) is weak or broken, and/or inner spring (6) is weak or broken.

  • Incorrect outer spring (7) and/or inner spring (6).

  • The primary pressure setting is incorrect. Perform the test in the Testing and Adjusting, "Primary Pressure for Lockup Clutch and Solenoid Valve (Torque Converter) - Test and Adjust".

Note: Modulating reducing style and ECPC style lock up clutch valves require software with different application codes. Refer to Special Instruction, REHS4541, "Software Configuration Guide{3168, 4800, 4808, 7600, 7610, 7620}".

Problem: The oil pressure slowly decreases or the low pressure remains with the lockup clutch solenoid deactivated.

Probable Cause

  • Load piston (3) is stuck and/or selector piston (2) is stuck.

Problem: The oil pressure is too high with the lockup clutch solenoid activated.

Probable Cause

  • The primary pressure setting is incorrect. Perform the test in the Testing and Adjusting, "Primary Pressure for Lockup Clutch and Solenoid Valve (Torque Converter) - Test and Adjust".
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.