YOKE AS 8Y0805 - Caterpillar

The oil pressure is too high
Probable Cause
The setting of the relief valve of the selector and pressure control valve is too high.Problem
Torque Converter Lockup Clutch (Pilot Pressure)
The oil pressure is too low.
Probable Cause
The pressure reduction valve is sticking.
The pressure reduction valve is incorrectly set. Add shims. The oil pressure is too high.
Probable Cause
The pressure reduction valve is sticking.
The pressure reduction valve is incorrectly set.There is oil pressure when the lockup clutch solenoid is deactivated.
Probable Cause
The lockup clutch solenoid is not operating correctly.The oil pressure slowly decreases or the pressure remains at 1725 kPa (250 psi) or less after the lockup clutch solenoid is deactivated.
Probable Cause
The lockup clutch solenoid is not operating correctly.
The shuttle valve in the synchronizing valve is stuck.Problem
Torque converter lockup clutch (leakage)
More than 3.8 L (1 US gal) of oil comes out of the pressure tap.
Probable Cause
There are bad seals in the lockup clutch.Problem
Torque Converter Lockup Clutch (Maximum Pressure)
There is oil pressure when the lockup clutch solenoid is deactivated.
Probable Cause
The selector piston is stuck.
The spring is weak or broken.
The shuttle valve is stuck.
The lockup clutch solenoid is bad.There is no oil pressure when the lockup clutch solenoid is activated.
Probable Cause
There is either a small amount of pilot oil or no pilot oil.
Operation of the shuttle valve is incorrect.
The outer spring is weak or broken.
The inner spring is weak or broken.The oil pressure is too low with the lockup clutch solenoid in the activated position.
Probable Cause
The load piston plug is not installed.
The load piston orifice is plugged.
The load piston is stuck.
The selector piston is stuck.
The outer spring is weak, broken or incorrect.
The inner spring is weak, broken or incorrect.
The primary pressure setting is incorrect.The oil pressure slowly decreases or the low pressure remains with the lockup clutch solenoid deactivated.
Probable Cause
Operation of the shuttle valve is incorrect.
The load piston is stuck.
The selector piston is stuck.
The primary pressure setting is incorrect. The oil pressure is too high with the lockup clutch solenoid in the activated position.
Probable Cause
The primary pressure setting is incorrect.Problem
Torque Converter Lockup Clutch (Primary Pressure)
The primary pressure is too low.
Probable Cause
The load piston and/or the selector piston is stuck.
The outer spring is weak, broken or incorrect.
The inner spring is weak, broken or incorrect.The primary pressure is too high.
Probable Cause
The outer spring or the inner spring is incorrect.
The modulation reduction valve is set incorrectly. Remove shims .Problem
Relief Valve Pressure (Torque Converter Inlet)
The pressure for the power train pump (charging) is correct, but the pressure at the torque converter inlet is too low.
Probable Cause
The torque converter inlet relief valve is open.
There is too much leakage in the transmission hydraulic control.
There are bad seals in a clutch of the transmission.
The torque converter outlet relief valve is not correctly set.The torque converter inlet pressure is too high.
Probable Cause
The torque converter inlet relief valve is set too high.Problem
Relief Valve (Torque Converter Outlet)
The engine speeds are out of specification.
Probable Cause
Refer to the engine system Troubleshooting, RENR1366, "P-312 Can Not Reach Top Engine RPM" for problems that involve the engine.
The torque converter has failed.The