A/T - Gear Whine Between 20 And 40 MPH: Overview
File In Section: 7 - TransmissionBulletin No.: 77-71-55A
Date: April, 1998
Subject:
Transaxle Gear Whine Noise Between 20 and 40 Mph (32 and 64 kmph) (Replace Final Drive)
Models:
1995-96 Buick Park Avenue
1995-97 Buick LeSabre
1995-96 Oldsmobile Ninety Eight
1995-97 Oldsmobile Eighty Eight
1997 Oldsmobile LSS, Regency
1995-97 Pontiac Bonneville
with 3.8L Engine (VINs K, L - RPOs L36, L27) and HYDRA-MATIC 4T60-E
Transaxle (RPO M13) with 2.84 Final Drive Ratio (RPO F17)
Transaxle Models: 5YMW, 5ASW, 6ASW or 7ASW
This bulletin is being revised to clarify models affected. Please discard Corporate Bulletin Number 77-71-55 (Section 7 - Transmission).
Condition
Some owners may experience a transaxle gear whine noise on coast down or light acceleration between 20 and 40 mph (32 and 64 kmph).
Cause
This noise condition may be generated by the transaxle final drive assembly. Vehicle body structure and powertrain mounting can make this noise more noticeable in some vehicle platforms.
Correction
A revised final drive assembly with a "fine pitch" gear geometry and 2.86 ratio is available to reduce final drive gear noise in 1995-1997 C/H vehicles with normally aspirated engines (RPO L27 or L36) and a 2.84 final drive ratio (RPO F17). Only 1997 H body vehicles with the 3.8L (VIN K, RPO L36) engine and a 7ASW transaxle code will require a calibration change by reflashing the PCM.
Parts Information
Refer to the current GMSPO parts catalog for the latest part numbers.
C/H-cars (Park Avenue, Ninety Eight Regency, Bonneville, Eighty Eight Royale, LeSabre, LSS)
Transaxle Model Final Drive
5ASW, 5YMW, 6ASW, 24209628 Final Drive
and 7ASW Assembly
Calibration Information: Calibrations are on CD 13.
New Calibration Numbers For 97 H Body Vehicles With a 7ASW Transaxle By RPO Options and Tire Size:
16268484 L36 NF2, P205 or P215
16268504 L36 NB7, P205 or P215
16268524 L36 K29 (EXPORT), NF2, P205,
or P215
16268544 L36 NF2, P225
16268554 L36 NB7, P255
16268564 L36 K29 (EXPORT), NF2, P225
Warranty Information
For vehicles repaired under warranty, use the table.