Suspension - Thud/Clunk Noise From Rear Springs

File In Section: 3 - Steering/Suspension

Bulletin No.: 73-34-02

Date: February, 1997

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 the following VIN Breakpoints:

Model 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 maneuver 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 maneuvers 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 maneuvers.

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)

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 Identification 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 Labor Time
E5027 Use published labor
operation time.