GM Service Manual Online
For 1990-2009 cars only

5th/6th Synchronizer Assemble


    Object Number: 648050  Size: SH

    Important: When you service the synchronizers, retain in order the components that you remove.

  1. Install the synchronizer blocking rings to the synchronizer hub. Align the tabs of the ring with the slots in the hub.
  2. Install the lateral plunger springs to the synchronizer blocking rings.

  3. Object Number: 648060  Size: SH
  4. Install the synchronizer sleeve on the hub. The flat area on the sleeve position on the hub with lateral plunger springs.

  5. Object Number: 648062  Size: SH
  6. Install the synchronizer blocks, the shift block plungers, and the springs in the hub.
  7. Position the sleeve in the neutral position in order to hold the shift block plungers and springs in place.

3rd/4th Synchronizer Assemble


    Object Number: 648064  Size: SH

    Important: When you service the synchronizers, retain in order the components that you remove.

  1. Install the synchronizer sleeve on the hub. The 3rd gear side of the center of the hub protrudes and has grooves. The 4th gear side of the sleeve has double ridges.

  2. Object Number: 648066  Size: SH
  3. Install the block, the shift block plunger, and the springs in the hub.
  4. Position the sleeve in the neutral position in order to hold the shift block plunger and springs in place.

  5. Object Number: 648053  Size: SH
  6. Install the following synchronizer rings to the synchronizer hub:
  7. • The blocker ring
    • The center ring
    • The inner ring

1st/2nd Synchronizer Assemble

The 1st gear is not synchronized. The 2nd gear synchronizer is assembled during assembly of the mainshaft.