A/T - 4T65-E, No Reverse Hot/Slips in Reverse
Bulletin No.: 04-07-30-033Date: August 04, 2004
TECHNICAL
Subject:
No Reverse Hot, Transaxle Slips In Reverse When Hot, Bump In Reverse Hot (Retighten Valve Body Bolt (379) and Replace Channel Plate Gasket)
Models:
2003-2004 Cars
with 4T65-E Transaxle (RPO's MN3, MN7, M15 or M76)
Condition
Some customers may comment that the vehicle slips in reverse when hot, no reverse when hot, or they feel a bump when shifted into reverse when hot.
Cause
There are multiple possible causes. Listed below are some of the possible causes:
^ Low Transaxle fluid level.
^ Reverse Servo Cover snap ring out of retaining groove.
^ Reverse Servo Piston seal rolled or cut.
^ Channel Plate flatness out of specification.
^ Channel Plate alignment holes improper depth.
^ Valve Body bolt (379) incorrectly torqued.
Correction
Follow the procedure below for diagnostic tips and repair procedures.
1. Inspect the reverse cover retaining ring for proper seating/retention.
^ If the ring is incorrectly seated, reset the retaining ring.
^ If the retaining ring is properly seated, continue with the next step.
2. Perform a transaxle line pressure check in reverse. This will test the reverse servo piston seal for leaks.
^ If the line pressure test is out of specification, inspect/repair the reverse servo piston seal. Refer to:
- Reverse Servo Replacement w/3.4L Engine SI Document ID # 1485540
- Reverse Servo Replacement w/3.8L Engine SI Document ID # 1485543
^ If the line pressure test is within specification, continue with the next step.
3. Remove the transaxle side cover. Refer to the appropriate SI Document.
4. Inspect valve body bolt (379) for breakaway torque of 16 N.m (11 lb ft).
^ If valve body bolt (379) is found loose, replace the channel plate gaskets, P/N 24206391, and retighten the valve body.
^ If the valve body bolt is found not to be loose, continue with the next step.
5. For additional reverse diagnostic information, refer to Slips in Reverse or No Reverse SI Document ID # 54866.
Parts Information
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use the table.
Disclaimer