COVER AS 5G5956 - Caterpillar

Table 1
Tools Needed     Qty    
6V-3079 Pressure Hose Assembly     1    
6V-4143 Coupler Assembly     2    
8T-0856 Pressure Gauge (
6000 kPa (870 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 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 power train charging section of the transmission oil pump is good.
The relief valve of the selector and pressure control valve is correctly set.Procedure
Illustration 1 g00652846
(A) Pressure Tap for the Charging Pressure of the Transmission
Use a coupler and a hose to connect a 8T-0856 Pressure Gauge (6000 kPa (870 psi)) to the nipple at pressure tap (A) .
Start the engine while the parking brakes are engaged. Run the engine at the low idle rpm with the transmission in NEUTRAL. The pressure on the gauge should be a minimum of 2688 34 kPa (390 5 psi).
Run the engine at the high idle rpm with the transmission in NEUTRAL. The maximum pressure on the gauge should be 3220 110 kPa (467 16 psi).
When this test is complete, stop the engine and remove the test equipment.Problem
The oil pressure is too low at low idle and the oil pressure is too low at high idle.
Probable Cause
Failure of the power train charging section of the transmission oil pump.
There are bad seals in a clutch of the transmission. Refer to Testing and Adjusting, "Clutch Pressure for Transmission Hydraulic Control Valve - Test and Adjust".Problem
The oil pressure is too low at low idle and the oil pressure is correct at high idle.
Illustration 2 g00525139
(1) Relief valve (2) Spacers
Table 2
Chart Of Spacers For The Relief Valve (1)    
Pt. No. of the Spacer     Thickness     Change in Pressure    
145-0105 Spacer    
0.25 mm (0.010 inch)    
41 kPa (6.0 psi)    
145-0106 Spacer    
0.90 mm (0.035 inch)    
145 kPa (21.0 psi)    
145-0107 Spacer    
1.60 mm (0.063 inch)    
261 kPa (37.9 psi)    
( 1 ) Before an adjustment is made, be certain that the valve spring is not weak or broken.Probable Cause
The setting of relief valve (1) is too low. Add spacers (2). Refer to Table 2. Adjust the relief valve to the low idle setting.
There are bad seals in a clutch of the transmission. Refer to Testing and Adjusting, "Clutch Pressure for Transmission Hydraulic Control Valve - Test".Problem
The oil pressure is too high
Probable CauseThe setting of relief valve (1) is too high. Remove spacers (2). Refer to Table 2. Adjust the relief valve to the low idle setting.