A/T - Converter Clutch Shudder

TSB 86-12 (Mar)

SUBJECT: GM CONVERTER CLUTCH SHUDDER

PROBLEM: Converter Clutch Shudder

CAUSES:
There are several possible causes of converter clutch shudder. Most of them are located in the pump area. Causes such as: control valve hanging, or broken spring; solenoid leakage; pump face leakage; and others.




One commonly overlooked area is the front turbine shaft (stator support) bushing (See figure).

A loose bushing will allow converter clutch apply pressure to leak into the release side of the converter. During lock-up, the release flow is directed to exhaust, and therefore apply pressure is also exhausted when the bushing is loose. The resulting lower apply pressure will allow the clutch to slip.

Generally, the shudder gets worse with higher temperatures and sometimes the clutch may cease to apply when hot. Severe cases may not lock-up at all, even cold. For example: A late 700 R4 "350" spline pump used with an early 700 R4 "200" spline turbine shaft and drum.