GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 Canyon Pickup - 4WD 🢒 Transmission/Transaxle 🢒 Manual Transmission - Aisin AR5 🢒 Synchronizers Assemble

Reverse/5th Gear Synchronizer

    Object Number: 881078 Size: SH

    Important: Lubricate the synchronizer parts with transmission fluid during assembly.

  1. Install the springs to the inserts and slide the inserts into the reverse gear outer blocking ring.

    2. Object Number: 881236 Size: SH
  2. Install the reverse/5th gear inner blocking ring (278) to the reverse/5th gear internal blocking ring (277).
  3. Turn the inner ring (278) to attach to the internal ring (277). Align the tabs 90 degrees from the slots.

    4. Object Number: 945696 Size: SH
  4. Install the 5th gear outer blocking ring on the reverse/5th gear internal and inner rings. Align the outer ring lugs to be in between the locking tabs on the inner ring.
  5. Install the reverse/5th rings to the reverse gear outer blocking ring.
    6. • The outer ring lugs align the reverse ring lugs.
    • The inner ring locking tabs will be in the release position on the reverse ring.

    Object Number: 881237 Size: SH
  6. Rotate both the inner and internal rings to lock the inner ring tabs to the reverse gear outer blocking ring.
    7. • The inner ring should still be locked to the internal ring.
    • All of the 5th/reverse blocking rings should stay together as an assembly if properly locked.

    Object Number: 881239 Size: SH
  7. While pushing the 3 inserts, install the 5th/reverse blocking ring assembly to the 5th/reverse synchronizer sleeve. The shoulder of the sleeve with the step goes forward. The rings are installed from the rear side.

3rd/4th Gear Synchronizer

    Object Number: 881243 Size: SH

    Important: The 3rd/4th gear synchronizer hub cannot be used again after removal. Always install a new hub.

  1. Install the synchronizer spring in the hole of a new 3rd/4th gear synchronizer hub.
  2. Slide the insert in while pushing down on the spring.

    3. Object Number: 880957 Size: SH
  3. Install the 3rd/4th synchronizer sleeve on the hub while pushing in the inserts.
    4. • The shoulder of the sleeve with the step goes forward, 4th gear side.
    • The smooth side of the hub, without the indents for synchronizer tabs, is the 4th gear side.
    • Align the inserts with the non-tooth areas of the sleeve.

    Object Number: 880955 Size: SH
  4. Install the following components to the 3rd/4th gear synchronizer hub (235):
    5. 4.1. The 3rd gear outer blocking ring (236)

    Ensure the tabs align in the hub.

    4.2. The 3rd gear internal blocking ring (237)
    4.3. The 3rd gear inner blocking ring (238)

    Ensure the tabs align in the hub

    The 4th gear blocking ring is installed with the input gear.

1st/2nd Gear Synchronizer

    Object Number: 881243 Size: SH
  1. Install the synchronizer spring in the hole of the 1st/2nd gear synchronizer hub.
  2. Slide the insert in while pushing down on the spring.

    3. Object Number: 881242 Size: SH
  3. Install the reverse gear on the hub while pushing in the inserts.
    4. • The forward, 2nd gear, side of the reverse gear has the shift fork groove.
    • The 2nd gear side of the hub has the internal splines indented from the thrust surface.
    • Align the inserts with the non-tooth areas of the sleeve.

    Object Number: 880952 Size: SH

    Important: When you service the synchronizers, retain them in the order that they are removed. Keep the synchronizer components together and mark to identify the correct location.

  4. Install the following components to the 1st/2nd gear synchronizer hub (215). Ensure the tabs on the rings are aligned with the notches in the hub.
    5. • The 2nd gear inner blocking ring (228)
    • The 2nd gear internal blocking ring (227)
    • The 2nd gear outer blocking ring (226)
    • The 1st gear outer blocking ring (216)
    • The 1st gear internal blocking ring (217)
    • The 1st gear inner blocking ring (218)