TRUNNION ASSEM. 7N9590 - Caterpillar

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 1 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.
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 1 g01225624
Pressure tap for the 312-4306 Lockup Clutch Valve effective on FRT00001-FRT01198.
Illustration 2 g03105877
367-9108 Lockup Clutch Valve and Mounting Gp effective on FRT01199-.
(1) Pressure tap
Connect 198-4240 Digital Pressure Indicator to the nipple at the pressure tap for the lockup clutch pressure.
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).
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).
Disconnect the harness from the lockup clutch solenoid. The pressure on the gauge must be 0 kPa (0 psi).
Stop the engine. After the pressure is correctly set, remove the test equipment.
Illustration 3 g01726694
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)