VALVE GP-SERVO 4T2544 - Caterpillar

Torque Converter Lockup Clutch Primary Pressure - Test and Adjust
Table 1
Required Tools    
Part Number     Part Descriptions     Qty    
6V-3079     Hose As     1    
6V-4143     Coupler     2    
8T-0849     Pressure Gauge (0 to 2,000-kPa (0 to 290-psi))     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.
Personal injury or death can result from sudden machine movement.Sudden movement of the machine or the release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury before testing and adjusting the power train system, perform the procedure in the Testing and Adjusting, Troubleshooting, "General Information" section.
This test will show the correct lockup clutch pressure if the lockup clutch pressure is correctly adjusted.Procedure
Illustration 1 g01374079
Synchronizing valve (1) Spring (2) Load piston plug (3) Shims (4) Cover (5) Load piston (6) Selector piston
Remove cover (4) from the torque converter lockup clutch and solenoid valve.
Remove load piston plug (2). Install cover (4) .
Illustration 2 g01387280
Torque converter lockup clutch and solenoid valve (A) Pressure tap for lockup pressure (7) Harness connector for lockup solenoid (8) Lockup solenoid
Disconnect electrical harness at connector (7) for lockup clutch solenoid (8) .
Using a 2-pin sure seal connector, two alligator clips and two 16-gauge wires approximately 4.5 m (15 ft) long, make a jumper harness. Connect the clip ends of the jumper harness to the positive (+) and negative (-) terminals of the machine battery. This will supply + 24 Volts to activate the lockup solenoid.
Use a coupler and a hose to connect a 8T-0849 Pressure Gauge (0 to 2,000-kPa (0 to 290-psi)) to the nipple at pressure tap (A) .
With the parking brake engaged, start and run the engine at low idle rpm with the transmission in NEUTRAL.
Look at the pressure gauge and connect the connector end of the jumper harness to the connector of the lockup solenoid. The pressure on the gauge should be 620 35 kPa (90 5 psi).
Stop the engine. After the pressure is correctly set, remove the test equipment. Remove cover (4). Install load piston plug (2). Install cover (4) .
Table 2
Chart of Shims for the Modulation Reduction Valve (1)    
Part No. for the Shims     Thickness of the Shims     Change in Primary Pressure as a Result of One Shim    
8J-4452 Shim    
0.12 mm (0.005 inch)    
10 kPa (1.5 psi)    
2S-0675 Spacer    
0.40 mm (0.016 inch)    
32 kPa (5.0 psi)    
9J-1330 Shim    
0.79 mm (0.031 inch)    
62 kPa (9.0 psi)    
( 1 ) Before an adjustment is performed, be certain that the valve springs are not weak or broken.Problem: The primary pressure is too low.
Probable Cause:
Load piston (5) is stuck, and/or selector piston (6) is stuck.
Spring (1) is weak or broken.
Incorrect spring (1) .
The