Cutlass Ciera FWD V6-181 3.0L (1984)
Governor Pressure Switch: Customer Interest
A/T - Torque Converter Clutch Shudder
SUBJECT
THM 125C TORQUE CONVERTER CLUTCH
NUMBER: 84-T-16
SHUDDER DIAGNOSIS
DATE:
Aug. 22, 1984
MODELS/YEARS
1982-84 CUTLASS CIERA, OMEGA & FIRENZA
SECTION: 7A
This bulletin summarizes and supersedes Dealer Technical Bulletins 82-T-19 and 83-T-16.
Some THM 125C transaxles may exhibit torque converter clutch (TCC) shudder as the TCC applies and/or after it applies when the accelerator Pedal is
depressed slowly (crowd shudder). These types of shudders are best described as a jerking sensation. In some cases the shudder may cause the instrument
panel to vibrate.
Listed below are items which may cause a "TCC Apply Shudder" and/or a "TCC Crowd Shudder":
TCC APPLY
TCC CROWD
SHUDDER
SHUDDER
X
X
1. An intermittent incorrect signal from the vehicle speed
sensor (V.S.S.). Dirt or grease on the reflective bar in the V..S.S. may be sending an incorrect or erratic
signal so that the converter clutch engages early. Remove the V.S.S. and clean it.
X
X
2. The auxiliary valve body cover attaching bolts may be loose
or the bolt threads/holes may be shallow. If the holes are shallow, the bolts will bottom out without
tightening the cover down.
X
3. Some 1982 models were built with either an exhaust hole
or an orifice cup plug in the auxiliary valve body cover. The auxiliary valve body cover was changed to a
solid cover (no exhaust hole or orifice cup plug) in 1982. The service auxiliary valve body cover, part no.
8643645 should be used on all models to prevent shudder. The service part does not have an orifice cup
plug.
FIGURE 1 - AUXILIARY VALVE BODY (COVER SIDE)
X
4. There are two types of auxiliary valve bodies in service.
One has a orifice cup plug and the other does not. See Fig.
1.
If the transaxle being serviced has the auxiliary valve body with the orifice cup plug, particles of the auxiliary valve body cover gasket may