M/T - Click Noise or Gear Disengagement in Reverse
File In Section: 7 - TransmissionBulletin No.: 67-72-04
Date: December, 1996
Subject:
Click Noise or Gear Disengagement in Reverse
(Install Revised Gear Set)
Models:
1995-96 Chevrolet Cavalier
1995-96 Oldsmobile Achieva
1995-96 Pontiac Sunfire, Grand Am
with Isuzu 5-speed Manual Transaxle (RPOs MJ1, MK7)
Condition
Some owners may comment on a clicking noise, with vehicle in motion, in the reverse gear.
You may also receive comments concerning the above transaxles with disengagement in the reverse gear.
Cause
The Isuzu transaxle uses a typical spur (straight cut) gear design in its reverse gear system. All spur gears have a potential of disengagement when excessive loads are applied or released.
This excessive load can occur when the vehicle is driven at a high or sudden increase of speed in reverse and then the throttle is quickly released. This is NOT a recommended driving technique.
A total or partial disengagement of the reverse gear may result in excessive backlash of the gear system. Excessive gear backlash may result in a click noise in reverse.
While the above conditions may cause customer concerns, it is not a transaxle durability issue.
Correction
A revised gear set is available to address the click noise or gear disengagement in reverse.
The revised gears consist of a reverse idler gear and a 1st/2nd/reverse synchronizer sleeve. These gears have been revised from spur-cut teeth to a "slight" helical teeth configuration. Helical gears tend to stay in position when load is applied.
Service Procedure
Important:
All components not mentioned below should be transferred to the proper shaft(s) as required per Section 7B3B of the appropriate "Transmission Transaxle Transfer Case Unit Repair Manual". The 1997 unit repair manual is applicable for both the 1995 and 1996 model year Isuzu transaxle. The 1997 manual contains the latest updated information.
Inspect and clean interior of transmission for any metal shavings or debris.
Verify you have received the correct input shaft (16).
For transmission RPO "MJ1" (Engine RPO "LD2"; VIN Code D & "LD9"; VIN Code T) there is NO notch cut on the OD of the reverse gear (straight teeth).
For transmission RPO "MK7" (Engine RPO "LN2"; VIN Code 4). there is an one (1) notch cut on the OD of the reverse gear (straight teeth).
Incorrect shafts will prevent assembly of the transaxle.
Do NOT re-use input shaft nut (31) and output shaft nut (60).
1. Install new stopper plate (88) and press new collar (bearing inner race) (87) onto new input shaft (16)
2. Remove existing 1st/2nd/reverse synchronizer sleeve (37) and replace with revised 1st/2nd/reverse synchronizer sleeve (37).
Important:
Note the direction of sleeve before disassembly. Revised sleeve must be reassembled in the same direction.
Each open portion of the insert spring should face the opposite direction from each other.
3. Remove existing reverse idler gear (61) and replace with revised reverse idler gear (61).
Important:
Use NEW input shaft nut (31) and output shaft nut (60). They must be properly tightened to 128 N.m (94 lb.ft.) and retained with thread locking material (GM Part No. 12345493). Use care not to allow the material to flow into the splines of the 5th gear and input shaft.
Staking of the nuts after tightening is also necessary.
Failure to properly install the nuts may result in transaxle shifting concerns.
4. Install revised reverse detent spring (50).
Parts Information
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Labor Time
K3145 Use published labor
Operation time.
ADD "To recondition transaxle completely".