Cutlass Supreme FWD V6-189 3.1L (1989)
Figure 2 - Update Calibration Components
CONDITION:
Some 1989 Cutlass Supreme models equipped with 3.1L engine and 4 speed automatic transmission may exhibit one or both of the following reverse
shudder conditions:
A.
"Apply" Shudder - When the driver accelerates from a standstill (with transaxle in reverse) the vehicle shudders.
B.
"Lift-Foot" Shudder - When the driver accelerates at light to medium throttle (with transaxle in reverse) then quickly lifts their foot off
the throttle the vehicle shudders.
Some of these vehicles may also exhibit a 3-2 tip-in flare condition at 21-24 mph.
SERVICE PROCEDURE:
(Figures 1 and 2)
To repair either of the reverse shudder conditions install a new vacuum modulator pipe assembly which incorporates an in-line .031 "brass orifice.
In the unlikely event that the new modulator pipe doesn't eliminate the reverse shudder, an updated calibration package may be installed on any OCJH,
OCHH, OYLH, or OYKH model transaxle built before (Julian date 086) March 27, 1989. All units built after Julian date 086 were built with the updated
calibration. The updated calibration package cannot be used on any other models.
If the new modulator pipe and updated calibration package doesn't eliminate the shudder then reference the 440-T4 Transaxle Diagnosis section in the
W-car Service Manual for other potential causes.
To repair a 3-2 tip-in flare condition, on a vehicle equipped with a OCJH, OYLH, OCHH, or OYKH model transaxle built before (Julian date 086)
March 27, 1989, an updated calibration package may be installed.
SERVICE PARTS:
Part Number
Description
Model Year
Model Usage
