Synchronizers Assemble (M3L)

If you are servicing this transmission for a shifting concern such as clash, hop out of gear, or block-out in a particular gear, the following hardware must be replaced as a set for the gear in question. Adjoining gears do not need to be serviced unless necessary:

• Main gear in question - for example 2nd, 3rd
• Synchronizer assembly, slider sleeve assembly
• Blocker ring assembly
• Shift fork inserts, pads

1st/2nd, 3rd/4th, 5th/6th Synchronizers

Fig 1: Scribe Mark On Synchronizer Hub And On Sleeve
Courtesy of GENERAL MOTORS COMPANY
1. Check the synchronizer assembly scribe marks for correct positions.
Fig 2: Synchronizer Sleeve, Synchronizer Inserts And Hub
Courtesy of GENERAL MOTORS COMPANY
2. Install the inserts (1) with the slots facing the hub.
3. Install the synchronizer sleeve (2) to the hub (3) (align the insert openings in the hub with the cuts in the synchronizer sleeve).

Reverse Synchronizer

Fig 3: Scribe Mark On Synchronizer Hub And On Sleeve
Courtesy of GENERAL MOTORS COMPANY
1. Check the synchronizer assembly scribe marks for correct positions.
Fig 4: Synchronizer Sleeve, Hub & Inserts
Courtesy of GENERAL MOTORS COMPANY
2. Install the inserts (3) with the slots facing the hub.
3. Install the synchronizer sleeve (1) to the hub (2) (align the insert openings in the hub with the cuts in the synchronizer sleeve).