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EI07148 - Bump Thump Felt from Driveline or Rear Suspension after Braking (Engineering Information)

Subject:EI07148 -- Bump Thump Felt from Driveline or Rear Suspension after Braking (Engineering Information)

Models:2007 Buick Rainier
2007 Chevrolet TrailBlazer
2007 GMC Envoy

Attention: Proceed with this bulletin ONLY if the customer has commented about this concern AND the EI number is listed in GMVIS. If the customer has not commented about this condition or the EI does not show in GMVIS, disregard the bulletin and proceed with diagnostics found in published service information. THIS IS NOT A RECALL- refer to TSB 04-00-89-053A for more detail on the use of Engineering Information bulletins.


Condition

Important:  If the customer did not bring their vehicle in for this issue, DO NOT proceed with this bulletin.

Some customers may comment on a bump-thump from the rear of the vehicle after coming to a complete stop. This condition may be felt intermittently and not necessarily after every stop.

Correction

GM Engineering is attempting to determine the root cause of this concern. GM has a need to obtain information first hand BEFORE any repairs are made. Record the following information on the repair order:

  1. Verify that the VIN and mileage listed on the RO is accurate.
  2. Can the condition be duplicated?
  3. When the condition was experienced;
  4.  - at approximately what speed had the vehicle been traveling prior to stopping?
     - was the braking considered to be slight, moderate or hard?
     - how long after being stopped did the bump-thump occur?
     - is the vehicle "cold" -- been sitting for a period of time? If so, how long?
     - did the condition occur on a flat surface or on a grade?
     - if equipped with auto rear leveling suspension (G67), did the compressor activate? If so, before or after the "Bump-Thump"?
     - if the vehicle is 4WD, what mode was the T case switch in? (Auto, 2WD, 4WD)

    Measuring propshaft angle:


    Object Number: 1976341  Size: SH

    Important: When recording propshaft angle, the vehicle must be on a flat surface or a drive on lift/ alignment rack (wheels must be supported).

  5. Record the propshaft angle using J 22910-4 (Inclinometer) as shown in the diagram above.
  6. Measuring driveline lash:


    Object Number: 1976346  Size: SH
  7. Record the Driveline lash. Install a dial indicator as shown in the diagram above.
  8. Contact the engineer, Jim Ivey at (517) 599-3384. Provide Jim with all information documented on the repair order. Jim will provide further repair information.

Warranty Information

Labor Operation

Description

Labor Time

F9710*

Engineering Information - Driveline

0.4 hr

*This labor operation number is for bulletin use only. This number will not be published in the labor time guide.