4-6. TRANSMISSION CHECKS.
Transmission Pressure Check. Transmission problems can be isolated by the use of pressure checks. When
the stall check indicates a slipping clutch, measure clutch pack pressure to determine if the slippage is due to low pressure
or clutch plate friction material failure. In addition, converter charging pressure and transmission lubrication pressure may
also be measured.
Transmission Mechanical Check. Prior to checking any part of the system for hydraulic friction (pressure
checking), the following mechanical checks must be performed:
Check mechanical inching from brake pedal to inching valve on transmission.
Check linkage from axle disconnect to disconnect actuator.
Check parking brake and inching pedal for correct adjustment and travel. Be sure the pedal moves freely
and returns fully.
Check that all linkages are properly connected and adjusted in each segment and at all connecting points.
Check wiring and electrical control components for obvious damage.
Check that cooling system is in good working order. Radiator fins must be clean to maintain proper cooling
and operating temperatures.
The engine must be fully operational to perform pressure checks.
Transmission Hydraulic Check. Before checking the transmission clutches, torque converter, charging pump,
and hydraulic circuits for pressure and rate of flow, it is important to make the following checks:
Check oil level in the transmission. The transmission fluid must be at the correct (full) level.
All clutches, converter, and fluid lines must be fully charged (filled) at all times during pressure checks.
The transmission fluid must be at operating temperature of 180-200OF (82-930C) to obtain correct
fluid level and pressure readings. Do not attempt to make these checks with cold oil.
To raise the oil temperature to 180-200OF (82-930C), operate (work) the vehicle or perform the STALL