TH48-E80 Petroleum Transmission Caterpillar

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 following conditions if the conditions exist:

• The torque converter is operating properly.

• The pressure for the torque converter inlet relief valve is correct.

• The pressure for the torque converter outlet relief valve is correct.

• The relief pressure for the lubrication system of the torque converter is correct.

Procedure

1. Install the 9U-7400 Multitach on the engine. The 9U-7400 Multitach can measure the engine rpm by using either the photo pickup and reflective tape, a magnetic pickup, or a tachometer generator.

   Note: The Electronic Control Analyzer Programmer (ECAP) or the Electronic Technician (ET) can be used instead of the multitach.

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   Illustration 1	g03028817
   right side view (1) Test port (torque converter inlet pressure) (2) Test port (torque converter outlet pressure) (3) Test port (planetary lubrication)

2. Connect 198-4240 Digital Pressure Indicator to pressure tap (1) for the inlet relief valve, to pressure tap (2) for the outlet relief valve and to pressure tap (3) for the lube relief valve.

3. Start the engine and increase engine speed to HIGH IDLE (approximately 1900 rpm).

4. Measure the pressures for the inlet relief valve, the outlet relief valve, and the lube relief valve.
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   Table 2

   Pressure kPa (psi)
   Control Manifold Gp	261-3051	367-2806
   Serial Number	FRT00001-FRT01198	FRT01199-UP
   Inlet Relief Valve	690 kPa (100 psi)	900 ± 70 kPa (131 ± 10 psi)
   Outlet Relief Valve	550 kPa (80 psi)	550 ± 28 kPa (80 ± 4 psi) at 1900 rpm in NEUTRAL
   Lubrication Relief Valve	310 kPa (45 psi)	276 ± 34 kPa (40 ± 5 psi)

5. Decrease engine speed and stop the engine.

6. If the pressures are not within the specifications, proceed to "Adjustment Procedure".

Adjustment Procedure

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Illustration 2	g01227484
261-3051 Control Manifold Gp effective on FRT00001-FRT01198 (1) Test port (torque converter inlet pressure) (2) Test port (torque converter outlet pressure) (3) Test port (Lube)

Note: This adjustment procedure applies to 261-3051 Control Manifold Groups which are effective with serial numbers FRT00001-FRT01198.

1. Loosen jam nut (6) on outlet relief valve (7).

2. Loosen jam nut (11) on inlet relief valve (12).

3. Turn set screw (5) for outlet relief valve (7) clockwise until the set screw bottoms out in order to increase the pressure for the torque converter outlet relief valve to the maximum pressure.

4. Turn set screw (9) for inlet relief valve (12) counterclockwise for two full turns.

5. Start the engine and run the engine at high idle (approximately 1900 rpm).

6. Turn set screw (9) for inlet relief valve (12) clockwise until the pressure at pressure tap (3) for lube relief valve (10) begins to drop or until the set screw bottoms out. The pressure at the inlet relief valve pressure tap (1) should be 662 ± 41 kPa (96 ± 6 psi).

7. Maintain the position of set screw (9) as you tighten jam nut (11).

8. Turn set screw (5) counterclockwise until the pressure at pressure tap (2) for outlet relief valve (7) is approximately 550 kPa (80 psi). Turn the set screw counterclockwise for an additional half of a turn. Then, turn the set screw clockwise until the pressure is approximately 550 ± 28 kPa (80 ± 4 psi).

9. Maintain the position of set screw (5) as you tighten jam nut (6).

10. Loosen jam nut (8) for lube relief valve (10).

11. Turn set screw (4) clockwise until the set screw bottoms out.

12. Turn set screw (4) counterclockwise for six turns. The pressure for lube relief valve (10) should be 310 kPa (45 psi). Adjust the set screw, if necessary. Pressures between 310 kPa (45 psi) and 434 kPa (63 psi) are acceptable.

13. Maintain the position of set screw (4) as you tighten jam nut (8).

14. Decrease the engine speed to low idle (800 rpm).

15. Check the pressure at pressure tap (3). The pressure for lube relief valve (10) should be 197 ± 41 kPa (28.5 ± 6 psi) with a minimum of 152 kPa (22 psi).

Illustration 3	g03100962
367-2806 Control Manifold Gp effective on FRT01199-UP (1) Control manifold (relief valve) (2) Lubrication relief valve (3) Torque converter outlet relief valve (4) Torque converter inlet relief valve (5) Test port (lube) (6) Temperature sensor for torque converter outlet (7) Test port (torque converter out pressure) (8) Test port (torque converter in pressure) (9) Supply port

The 367-2806 Control Manifold Group contains two non-adjustable valves, refer to Illustration 3. In the potential event of over-pressurization of the converter circuit, the converter inlet relief bypasses flow to the transmission sump to relieve pressure and prevent converter damage. The 148-1928 Relief Valve is a non-adjustable cartridge style design with a cracking pressure of 900 ± 70 kPa (130 ± 10 psi). Oil flows past the normally closed inlet relief valve, through the converter, and back to the manifold and flows across the converter outlet relief valve. This valve can be adjusted by adding or removing shims. Refer to Table 3. The target set point for the converter outlet relief valve is 550 kPa (80 psi) at 1900 rpm in NEUTRAL. Oil flows past the converter outlet relief valve to the lubrication relief valve. The 165-0390 Relief Valve is a non-adjustable cartridge style design with a cracking pressure of 275 ± 35 kPa (40 ± 5 psi). Oil flows past the lubrication relief valve to speed increaser or pump drive lube. Any oil that is bypassed by any of the three valves is returned to sump.

Note: Typical valves will require four 2R-4330 Washers and three to four 8J-6709 Shims. The entire shim stack should be 10.4 mm (0.41 inch) thick.

1. Loosen the STOR plug on the torque converter outlet relief valve (3). Remove the plug and the spring.

2. Insert shims below the spring in the spool.

   Note: Typical valves will require four 2R-4330 Washers and three to four 8J-6709 Shims. The entire shim stack should be 10.4 mm (0.41 inch) thick.

3. Install the spring and STOR plug. Tighten to 350 ± 53 N·m (258 ± 39 lb ft).

4. Start the engine and run the engine at high idle (1900rpm) with the transmission in NEUTRAL.

5. Check the torque converter outlet pressure (7).

6. Stop the engine.

7. Repeat Steps 1 through 6 until the torque converter outlet pressure is 550 ± 28 kPa (80 ± 4 psi).