CHUGGLE - (NEW CALIBRATION PROMS)

SUBJECT: CHUGGLE (NEW CALIBRATION PROMS)

VEHICLES AFFECTED: 1992-93 "B" CARS WITH 5.7L ENGINE (RPO LOS - VIN 7) AND AUTO TRANS

CONDITION:

--------- Some owners with vehicles listed below, equipped with 5.7L V8 engines (L05, VIN 7), may comment about a "chuggle" condition.

This bulletin addresses the following vehicle/condition problems ONLY:

Vehicle - Body Year(s) Condition -------------- ------- --------- Buick - Sedan & Wagon 1992-93 Chuggle with base axle only Sedan with RPO GM8, 2.56 ratio Wagon with RPO GU2, 2.73 ratio

Chevrolet - Wagon 1992-93 Chuggle with base axle only RPO GU2, 2.73 ratio

Oldsmobile - Wagon 1992 Chuggle with base axle only RPO GU2, 2.73 ratio

CAUSE:

----- Insufficient dampening of the torque converter and PROM calibration.

CORRECTION:

---------- New calibration PROMs have been released to address the above vehicle/condition problems.

The following PROMs are NOT RECOMMENDED for vehicles with OPTIONAL AXLE RATIOS or TRAILER TOWING PACKAGES.

Vehicles produced from mid-June 1993 through the end of the model year are expected to have this PROM change. Check PROM Scan ID.

Emission Service Scan Broadcast System Years Axle Ratio/Body PROM P/N ID Code -------- ----- --------------- ----------------------- Federal 92-93 2.56 (GM6)/Sedan 16195067 5131 BHHP (NA5) 2.73 (GU2)/Wagon 16195067 5131 BHHP California 93 2.56 (GM8)/Sedan 16195072 5141 BHHR (NB2) 2.73 (GU2)/Wagon 16195072 5141 BHHR

PLEASE NOTE: The above vehicles produced before December 16,1991 (Julian Date 350) may have Hydra-matic 4L60 Model 2DDM Transmissions. Model 2DDM Transmissions may contain torque converters with insufficient dampening.

Vehicles with Model 2DDM Transmission - Check dealer records to see if the torque converter has already been replaced with P/N 8650935 (Tagged B/C: DGAF). It is not necessary to replace those torque converters with P/N 8650935.

Transmissions with torque converters with P/N 8656959 (Tagged B/C: DG5F) need to have the torque converter replaced with P/N 8650935.

Model 2BRM transmissions (produced after December 16, 1991) have the new torque converter.

For vehicles repaired under warranty use:

Labour Operation Time ---------------- ---- Replace PROM 0.6 hour Replace Torque Converter 2.8 hours

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.