TRANSAXLE GEAR WHINE BETWEEN 20 & 40 MPH. Buick Park Avenue 1997

REVISION: 03/20/98

THIS BULLETIN IS BEING REVISED TO CLARIFY MODELS AFFECTED. PLEASE DISCARD CORPORATE BULLETIN NUMBER 77-71-55 (SECTION 7 - TRANSMISSION). ______________________________________________________________________

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

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.

SERVICE PROCEDURE

TO REPAIR THE VEHICLE, THE FOLLOWING STEPS MUST BE PERFORMED:

DRIVE THE VEHICLE AND CONFIRM THE FOLLOWING:

* THE NOISE IS ONLY PRESENT DURING A LIGHT ACCELERATION OR CLOSED THROTTLE DECELERATION BETWEEN 20 AND 40 MPH (32 AND 64 KMPH). * THE NOISE IS NOT PRESENT IN PARK OR NEUTRAL RANGES. * THE NOISE IS PRESENT IN 2ND, 3RD OR 4TH GEAR (DOES NOT GO AWAY IN 3RD GEAR).

IF ALL THE ABOVE CONDITIONS ARE MET, THE FINAL DRIVE ASSEMBLY SHOULD BE REPLACED.

1. VERIFY THE TRANSAXLE MODEL IS ONE OF THE FOLLOWING:

5YMW, 5ASW, 6ASW OR 7ASW

USE THE VIN INQUIRY OR HAVE THE DEALER INSPECT THE TRANSAXLE ID TAG. IF THE TRANSAXLE IS NOT ONE OF THESE MODELS, THERE IS NOT A FIX FOR THE FINAL DRIVE NOISE IN THAT MODEL AT THIS TIME.

2. ON 1995 MODELS, ORDER THE FINAL DRIVE ASSEMBLY, A 1996 STYLE 1-2 SUPPORT AND ROLLER ASSEMBLY, AND A 1996 STYLE SUN DRUM.

ON 1996 MODELS, ORDER THE FINAL DRIVE PACKAGE FOR THE APPROPRIATE TRANSAXLE MODEL AS LISTED UNDER SERVICE PARTS INFORMATION.

ON 1997 MODELS, ORDER THE FINAL DRIVE PACKAGE FOR THE APPROPRIATE TRANSAXLE.

IMPORTANT: REFLASH OF THE PCM CALIBRATION IS ONLY REQUIRED WHEN THE VEHICLE IS EQUIPPED WITH A 7ASW TRANSAXLE MODEL.

3. INSTALL THE QUIET FINAL DRIVE ASSEMBLY IN THE VEHICLE FOLLOWING THE PROPER SERVICE MANUAL PROCEDURE.

A PHONE CALL WILL BE REQUIRED TO PROPERLY REPROGRAM THE PCM WITH A NEW CALIBRATION ON 1997 H BODY VEHICLES WITH A 7ASW TRANSAXLE.

CALL THE TECHLINE CUSTOMER SUPPORT CENTER (TCSC) AT:

ENGLISH 1 800 828 6860 FRENCH 1 800 503 3222

INFORM THE TCSC SPECIALIST THAT YOU ARE RECONFIGURING THE VEHICLE DUE TO THE CHANGES MADE TO THE TRANSMISSION. YOU WILL NEED THE VEHICLES VIN AND THE NEW CALIBRATION PART NUMBER WHEN YOU CALL TCSC. TCSC WILL PROVIDE YOU WITH A SPECIAL NUMBER. THE NUMBER IS CALLED A VCI WHICH STANDS FOR VEHICLE CONFIGURATION INDEX. THIS NUMBER IS UNIQUE FOR EACH VEHICLE. THE NUMBER WILL UPDATE THE PCM WITH THE NEW CALIBRATION. TCSC WILL ALSO UPDATE THEIR DATA BASE SO THAT A PHONE CALL WILL NOT BE REQUIRED AFTER YOU RECEIVE YOUR NEXT CD ROM DISC.

ONCE YOU HAVE THE NUMBER FROM TCSC ENTER THE SERVICE PROGRAMMING SYSTEM, SELECT SPECIAL, AND THEN PROGRAM BY VCI. THE CORRECT CALIBRATION PART NUMBER WILL BE LISTED ON THE SPS SUMMARY SCREEN. CONTINUE WITH THE PROGRAMMING PROCESS BY SELECTING PROGRAM.

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, AND 7ASW 24209628 FINAL DRIVE 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: LABOR OPERATION: K7750 FINAL DRIVE ASSY.

USE APPROPRIATE ADD TIME TO REFLASH THE CALIBRATION ON 1997 H BODY MODELS ONLY. USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 00 ATTACHMENTS: 00

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.