NOISE AND/OR VIBRATION DURING LOW SPEED ACCEL. Buick Riviera 1999

SUBJECT: NOISE AND/OR VIBRATION DURING LOW SPEED ACCELERATION OR "BRAKE TORQUING" (REPLACE TRANSAXLE REAR MOUNT ASSEMBLY)

MODELS: 1999 BUICK PARK AVENUE, RIVIERA - BUILT PRIOR TO THE FOLLOWING VIN BREAKPOINTS:

MODEL VIN BREAKPOINT ============ ==============

PARK AVENUE X4623629 RIVIERA X4701065

CONDITION:

SOME CUSTOMERS MAY COMMENT ABOUT A NOISE AND/OR VIBRATION DURING LOW SPEED ACCELERATION OR DURING "BRAKE TORQUING". THIS SOUND MAY BE SIMILAR TO THAT OF THE EXHAUST SYSTEM CONTACTING THE FLOOR PAN.

CAUSE:

THE REAR TRANSAXLE MOUNT MAY BE GROUNDED OUT DUE TO A BOUND OR TWISTED CONDITION WITHIN THE MOUNT ASSEMBLY.

CORRECTION:

SERVICE PROCEDURE -

1. RAISE AND SUITABLY SUPPORT THE VEHICLE. REFER TO VEHICLE LIFTING AND JACKING IN THE GENERAL INFORMATION SECTION OF THE SERVICE MANUAL.

2. UNSNAP AND POSITION THE HEAT SHIELD ASIDE IN ORDER TO ACCESS THE UPPER TWO NUTS ON THE REAR TRANSAXLE MOUNT.

3. SUPPORT THE REAR OF THE TRANSAXLE ASSEMBLY WITH A SUITABLE FLOOR JACK.

4. REMOVE THE UPPER TWO NUTS RETAINING THE TRANSAXLE ASSEMBLY REAR MOUNT BRACKET TO THE TRANSAXLE REAR MOUNT.

5. REMOVE THE LOWER TWO BOLTS AND NUT RETAINING THE TRANSAXLE MOUNT TO THE ENGINE FRAME.

6. USE THE FLOOR JACK TO RAISE THE TRANSAXLE ASSEMBLY FOR CLEARANCE IN ORDER TO REMOVE THE REAR TRANSAXLE MOUNT.

7. REMOVE THE REAR TRANSAXLE MOUNT FROM THE ENGINE FRAME.

8. INSTALL THE REAR TRANSAXLE MOUNT TO THE ENGINE FRAME.

- USE THE FLOOR JACK TO LOWER THE TRANSAXLE ASSEMBLY UNTIL THE TRANSAXLE BRACKET CONTACTS THE REAR TRANSAXLE MOUNT.

- REPOSITION THE REAR TRANSAXLE MOUNT AS NECESSARY TO ALIGN THE MOUNTING HOLES.

- INSTALL THE LOWER TWO BOLTS AND NUT TO RETAIN THE TRANSAXLE MOUNT TO THE ENGINE FRAME.

- LOWER THE TRANSAXLE ASSEMBLY COMPLETELY ONTO THE REAR TRANSAXLE MOUNT.

9. TIGHTEN

- TIGHTEN THE LOWER TRANSAXLE MOUNT BOLTS TO 50 N.M (37 LB FT).

- TIGHTEN THE LOWER TRANSAXLE MOUNT NUT TO 50 N.M (37 LB FT).

10. INSTALL THE UPPER TWO NUTS TO RETAIN THE TRANSAXLE ASSEMBLY REAR MOUNT BRACKET TO THE TRANSAXLE REAR MOUNT.

TIGHTEN

- TIGHTEN THE UPPER TRANSAXLE MOUNT NUTS TO 40 N.M (30 LB FT).

11. REMOVE THE FLOOR JACK SUPPORTING THE TRANSAXLE ASSEMBLY.

12. INSTALL THE STEERING GEAR HEAT SHIELD.

13. INSPECT THE ENGINE FRAME MOUNTS

- ENSURE THAT THE FRAME MOUNTS ARE NOT BOUND UP AND ARE PROPERLY SEATED.

14. IF THE ENGINE FRAME MOUNTS ARE BOUND UP OR ARE NOT PROPERLY SEATED, PERFORM THE FOLLOWING:

- LOOSEN THE ENGINE FRAME MOUNT FASTENERS.

- UNBIND AND SEAT THE ENGINE FRAME MOUNTS ("SHAKE" THE ENGINE DOWN).

- TIGHTEN THE FASTENERS.

15. LOWER THE VEHICLE.

16. ROAD TEST THE VEHICLE AT THE COMPLAINT SPEED FOR A SUFFICIENT DISTANCE OR TIME.

PARTS INFORMATION:

P/N DESCRIPTION ============ ======================================

25693540 TRANS REAR MOUNT ASSEMBLY

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION LABOR OPERATION NUMBER DESCRIPTION TIME =============== ==================================== ===============

K6723 REAR MOUNT, TRANSAXLE - REPLACE 0.6 HR*

*THIS TIME IS UPDATED FROM THE CURRENT LABOR TIME GUIDE. THE NEXT UPDATE OF THE LABOR TIME GUIDE WILL CONTAIN THIS CHANGE.

ADD: TO TEST DRIVE VEHICLE 0.2 HR (AUTHORIZATION REQUIRED)

FIGURES: 01 ATTACHMENTS: 00

FIGURE 1 1. REAR TRANSAXLE MOUNT ASSEMBLY 2. BOLT TIGHTEN TO 50 N.M (37 LB FT) 3. NUT TIGHTEN TO 50 N.M (37 LB FT)

Object Number: 484773 Size: LF

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.