631E Series II, 633E Series II and 637E Series II Wheel Tractor Power Train Caterpillar

Illustration 1	g00635189
Selector Group (1) Relief valve for the transmission oil pump (2) Spacers

This test will determine the following condition:

• The transmission oil pump is good.

• The relief valve for the transmission oil pump (1) is set correctly.

Procedure

Illustration 2	g00635185
Left Side of Transmission (L) Pressure tap for transmission pump

1. At pressure tap (L), connect a hose group to the nipple assembly.

2. Connect a 8T-0855 Pressure Gauge to the hose.

3. While the parking brakes are engaged, start the engine and operate the engine at LOW IDLE rpm. The transmission should be in NEUTRAL. The pressure on the gauge should read 2760 ± 70 kPa (400 ± 10 psi).

4. Operate the engine at HIGH IDLE rpm with the transmission in NEUTRAL. The pressure on the gauge should read a maximum of 3310 kPa (480 psi).

5. When this test is complete, stop the engine. Remove the test equipment.

Results

Note: Before an adjustment is made, make sure that the valve spring is not weak or broken.

If the oil pressure is too low, the following conditions occurred:

• The transmission oil pump has failed.

• The setting of the relief valve for the transmission oil pump (1) is too low. Add spacers (2). Refer to Table 2. Adjust for LOW IDLE engine setting.

If the oil pressure is too high, the following conditions occurred:

• Setting of the relief valve for the transmission oil pump (1) is too high.

• Remove spacers (2). Refer to Table 2. Adjust for LOW IDLE engine setting.