Drivetrain - Driveline Moan/Vibration at 1200-1300 RPM
TECHNICALBulletin No.: 08-04-95-001
Date: May 02, 2008
Subject:
Driveline Moan Noise/Vibration at 1200 to 1300 RPM with TCC Engaged (Replace Differential Carrier Dampener and Bracket)
Models:
2008 Cadillac CTS
with 6L50 Automatic Transmission (RPO MYB)
Built Between and Including VIN Breakpoints 80155891 through 80156273
Condition
Some customers may comment on a loud moan noise or vibration from the driveline. This may occur under load or acceleration from 1200 to 1300 RPM with the TCC engaged. These conditions may not occur frequently, but the disturbance is very noticeable when the conditions are met. The concern may also result in a phasing or beating noise from the driveline at approximately 2500 RPM that may be noticeable under quiet conditions.
Cause
This concern may be caused by a ground-out condition in the mass dampener assembly attached to the rear axle. Some vehicles may have been assembled with an incorrect early design two-piece bracket for the dampener. The bracket has a rib that can contact the dampener (see photo above).
Correction
Inspect the mass dampener assembly for a two-piece bracket and check for contact between the rib on the bracket and the dampener. If this condition is verified replace the bracket and dampener assembly with P/N 19206434.
Parts Information
Warranty Information
For vehicles repaired under warranty, use the table.
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