Tahoe 4WD V8-6.0L Hybrid (2008)
Fluid Pump: Customer Interest
A/T - Chuggle/Shudder On Hard Acceleration
TECHNICAL
Bulletin No.: 09-07-30-001B
Date: April 19, 2011
Subject: Transmission Shudder or Bucking Feel (Follow Procedure Outlined Below)
Models:
2009 Cadillac Escalade
2008-2009 Chevrolet Tahoe
2008-2009 GMC Yukon
Equipped with 2 Mode Hybrid Automatic Transmission (RPO M99)
Built Prior to Serial Date 8010017028
Supercede:
This bulletin is being revised to update the Condition statement. Please discard Corporate Bulletin Number 09-07-30-001A (Section 07 -
Transmission/Transaxle).
Condition
Some customers may comment that the vehicle has a shudder or bucking feel when driving with the internal combustion engine running and the
transmission cold. The concern may be more noticeable in cold ambient temperatures. The concern can also be noticeable at highway speeds.
Cause
This condition may be caused by a restricted line pressure decrease orifice.
Correction
To verify the concern is caused by the orifice, monitor the Hybrid Low 1-2 clutch slip speed (clutch 1 on the scan tool). Normal clutch slip speed should
be 0 rpm. If the slip speed varies either positive or negative slip rpm, or causes other clutch slip speeds to read erratic, the orifice is most likely restricted
(see scan tool picture 1 below).
1. Remove the transmission.
2. Separate the torque dampener housing from the transmission.
3. Remove and discard the orifice cup plug in the pump cover. The location is shown above (callout #2).
