MG3, M86 Manual Transaxle Grinding or Growling Noise in 3rd or 4th Gear, Excessive Engagement or Disengagement Effort While Shifting into 5th or Reverse Gear, Will Not Shift into Either 5th or Reverse

This bulletin is being updated to add additional information on 5th or reverse gear in the Subject, Condition and Cause sections of this bulletin. Please discard Corporate Bulletin Number 07-07-29-001 (Section 07 -- Transmission/Transaxle - Manual Transmission).

Some customers may comment on any or all of the following conditions:

Diagnosis of the concern will lead the technician to replace the 5th/reverse gear synchronizer assembly and/or the 5th/reverse gear blocking rings on the output shaft of the transaxle to correct the condition. In order to access either the synchronizer assembly, the blocking rings, or any other components on the output shaft, the 4th gear must first be removed from the output shaft and then reinstalled after parts have been replaced.

The Service Manual procedure for output shaft assembly states that the 4th gear will install very tight. Some dealers have been unsuccessful in achieving the press loads required to completely seat the 4th gear on the output shaft during re-assembly, resulting in these dealers replacing the entire manual transaxle assembly.

Important:  Some technicians may have trouble when pressing gears on or off the output shaft of the Getrag™ MG3/M86 five-speed manual transaxle. The output shaft gears are not splined to the output shaft and are a very tight press fit.

If diagnosis leads to replacement of any components on the output shaft, dealers should follow published Service Information (SI) procedures and use the appropriate special tools to correctly re-assemble the output shaft.

Pressing Output Shaft Gears

Important: When pressing these gears on or off of the output shaft, care needs to be taken to ensure that the shaft is not nicked or have any burrs on it. (The shaft and gear need to be free of dirt or debris) Extreme care should be taken not to bind or cock the gear on the shaft. If this happens, press the gear back off the shaft and start over.

Press loads can reach 2-3 tons on the 4th fixed gear and 12-17 tons on the 3rd fixed gear (both located on the output shaft). The 3rd and 4th speed gears (on the input shaft) come off with minimal pressure but if trying to remove the 5th fixed gear and the 3rd speed gears at the same time, press loads in excess of 20 tons will not move the gear. Gears need to be removed and installed one at a time.

If dealers are not able to properly seat the 4th gear on the output shaft, a complete output shaft assembly for MG3 and M86 manual transaxles is being released as a field fix and should be used rather than replacing the manual transaxle assembly.

Part numbers for these output shaft assemblies and their applications are listed below:

For vehicles repaired under warranty, use: