Sierra 1500 2WD V6-4.3L (2008)
This bulletin is being revised to update the models involved and add Condition information. Please discard Corporate Bulletin Number 09-07-30-004B
(Section 07 - Transmission/Transaxle).
Condition
Note
Vehicles built prior to December 2008 are more likely to have leaking fluid seal rings. Starting in November 2008, a new 2-piece seal was implemented.
When the transmission pump is removed and a 2-piece seal (1) is found, do not continue on with this bulletin. The guidelines of this bulletin will not
apply to a 2-piece seal.
Some customers may comment on any of the following conditions:
-
Flare or harsh 2-3 shift
-
Bump/delay in 2-3 shift
-
Delayed/extended or delayed with harsh feel initial Park to Drive and/or Reverse to Drive shifts
Cause
This condition may be caused by leaking 1-2-3-4 and 3-5-R clutch fluid seal rings. The following conditions are indications that the fluid seal rings may
be leaking.
-
Delayed/extended or delayed with harsh feel initial Park to Drive and/or Reverse to Drive shifts that are more likely to occur when the
transmission temperature is below approximately 40°C (104°F).
-
Harsh or flaring 2-3 shifts that are more likely to occur when the transmission fluid temperature is in the approximately 0°C (32°F) to 40°C (104°
F) temperature range, but can be present at any temperature.
-
Harsh 2-3 shifts that are more likely to occur at less than 50% throttle pressure.
Correction
Important
DO NOT replace the transmission control valve body, transmission control module (TCM) or transmission fluid pump cover assembly.
1. Verify the customer's concern with the described conditions above. Then replace the 1-2-3-4 and 3-5-R clutch fluid seal rings.
2. Remove the transmission assembly from the vehicle. Refer to Transmission Replacement in SI.
3. Remove the transmission oil pan. Refer to Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement in SI.
Notice
When removing the transmission control valve body, discard the O-ring seals and install new seals, GM P/N 24236927. Failure to install control
valve body O-ring seals may cause internal transmission leaks and transmission damage.
4. Remove the transmission control valve body. Refer to Control Valve Body Assembly/Removal in SI.
5. Remove the transmission bell housing / fluid pump. Refer to Torque Converter Housing with Fluid Pump Removal in SI.
