For 1990-2009 cars

# THUD/CLUNK NOISE FROM REAR SUSPENSION

#### SUBJECT: THUD/CLUNK NOISE FROM REAR SUSPENSION (CHECK/REPLACE REAR SPRINGS)

#### MODELS: 1997 CHEVROLET VENTURE 1997 OLDSMOBILE SILHOUETTE 1997 PONTIAC TRANS SPORT WITH ELECTRONIC LEVEL CONTROL (ELC) (RPO G67)

BUILT PRIOR TO VIN BREAKPOINTS:

CHEVROLET - VD128902 OLDSMOBILE - VD129047 PONTIAC - VD129028

#### CONDITION:

SOME OWNERS OF VEHICLES ASSEMBLED PRIOR TO VIN BREAKPOINTS INDICATED ABOVE MAY COMMENT ABOUT A THUD/CLUNK TYPE NOISE FROM THE REAR SUSPENSION/SHOCK ABSORBERS. THIS CONDITION IS MOST APPARENT WHEN VEHICLE IS OPERATED OVER LARGE OBSTACLES SUCH AS SPEED BUMPS, CHUCK HOLES, RAILROAD TRACKS OR ANY MANUEVER WHICH UNLOADS THE REAR SUSPENSION.

#### IMPORTANT:

VEHICLES MUST BE PROPERLY EVALUATED TO INSURE CONDITION IS CORRECTLY DIAGNOSED. OTHER OPERATING MODES SUCH AS BRAKING OR ACCELERATION MANUEVERS MAY RESULT IN A SIMILAR NOISE CONDITION THAT WILL NOT BE CORRECTED BY THIS BULLETIN.

#### CAUSE:

THIS NOISE MAY BE CAUSED BY THE REAR SHOCK ABSORBERS EXTENDING TO FULL LENGTH, RESULTING IN AN INTERNAL CONTACT OF THE SHOCK PISTON WITH THE SHOCK ABSORBER CYLINDER TUBE. THIS CONDITION IS MOST LIKELY TO OCCUR ON VEHICLES WITH HIGH REAR BUMPER HEIGHTS (INCORRECT SPRINGS), BUT COULD STILL OCCUR ON SOME VEHICLES WITH CORRECT SPRINGS DURING SEVERE MANUEVERS.

#### CORRECTION:

IF VEHICLE WAS ASSEMBLED WITH A REAR SPRING OTHER THAN THOSE SHOWN IN THE CHART BELOW, REPLACE BOTH REAR SPRINGS WITH APPROPRIATE PARTS INDICATED FOLLOWING APPLICABLE SERVICE MANUAL PROCEDURE, SECTION 3D, REAR SUSPENSION.

#### REAR SPRING USAGE CHART - ELECTRONIC LEVEL CONTROL (RPO G67)

VEHICLE RPO SPRING TAG DESCRIPTION P/N CODE CODE =========== === ==== ==========

SHORT WHEEL BASE 10400895 8KJ, 9KJ TKJ

LONG WHEEL BASE 22132415 8BK, 9BK TBK

EXISTING SPRINGS ON VEHICLE CAN BE IDENTIFIED BY EITHER THE CODE FOUND ON TAGS ATTACHED TO SPRINGS OR BY SPRING RPO CODES FOUND ON THE SERVICE PARTS INDENTIFICATION LABEL. IF THESE CODES DO NOT CORRESPOND WITH THOSE ON CHART ABOVE, VEHICLE WAS ASSEMBLED WITH INCORRECT SPRINGS.

#### PARTS INFORMATION:

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: E5027 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.

COPYRIGHT 1997 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.