TH48-E80 Petroleum Transmission Caterpillar

Note: Transmissions FRT1-1198 have modulating reducing style lock up clutch valves. Transmissions ; FRT1199-Up have electronic clutch pressure control "ECPC" style valves. 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.

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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 correct lockup clutch pressure if the lockup clutch pressure is correctly adjusted.

Procedure

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Illustration 1	g01226695
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

1. Remove cover (1) from the torque converter lockup clutch and solenoid valve.

2. Remove load piston plug (4). Install cover (1).
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   Illustration 2	g01225624
   Pressure tap for lockup clutch pressure "LUC GAUGE" effective on FRT00001-FRT01198

3. Connect 198-4240 Digital Pressure Indicator to the nipple at the pressure tap.

4. Shift to FIRST gear and increase engine speed to 1900 rpm so the LUC engages. The primary pressure must be 944 ± 35 kPa (137 ± 5 psi).

5. Stop the engine. After the pressure is correctly set, remove the test equipment. Replace load piston plug (4).

Table 2

Chart Of Shims For The Modulation Reduction Valve(1)
Pt. No. for Shims	Thickness	Change in Primary Pressure
8J-4452 Shim	0.12 mm (0.005 inch)	12 kPa (1.8 psi)
2S-0675 Spacer	0.40 mm (0.016 inch)	39 kPa (5.7 psi)
9J-1330 Shim	0.79 mm (0.031 inch)	76 kPa (11.0 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 (3) and/or the 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 modulation reduction valve is set incorrectly. Add shims (5). Refer to Table 2.

Problem: The primary pressure is too high.

Probable Cause

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

• The modulation reduction valve is set incorrectly. Remove shims (5). Refer to Table 2.