GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Aveo 🢒 Transmission 🢒 Manual Transmission - Y4M 🢒 Synchronizer Assembly Inspection

    Object Number: 1223795 Size: SH
  1. Inspect the wear of the cone area. After matching synchronizer the ring to gear, measure between the gear and the ring. Replace if necessary.

    2. Specifications:

    • The standard clearance between the gear and ring is 1 mm (0.039 in).
    • The clearance limit between the gear and ring is 0.5 mm (0.020 in).

    Object Number: 1223803 Size: SH
  2. Inspect the cone contact condition. When synchronizer mechanism is abnormal in operation, connection between ring inner surface and gear cone area is considered to be partially defective in spite of correct clearance between gear and ring. Therefore, cone area and ring inner surface shall be inspected. In this case, ring inner surface shall be glossy. Black area is abnormal and if inspection is difficult, inspect after applying red lead. Cone area can be worn in wave form.

    3. Object Number: 1223775 Size: SH
  3. Inspect the key slot width of synchronizer ring. Measure key slot width of synchronizer ring. Replace if necessary.

    4. Specifications:

    • The standard key slot width for 1st gear is 9.6 mm (0.378 in).
    • The limit key slot width for 1st gear is 10 mm (0.394 in).
    • The standard key slot width for 2nd, 3rd, and 4th gear is 9.6 mm (0.378 in).
    • The limit key slot width for 2nd, 3rd, and 4th gear is 10 mm (0.394 in).
    • The standard key slot width for 5th gear is 9.4 mm (0.370 in).
    • The limit key slot width for 5th gear is 9.8 mm (0.386 in).

    Object Number: 1223784 Size: SH
  4. Inspect for worn or damaged synchronizer ring teeth. Replace if necessary.

    5. Object Number: 1223790 Size: SH
  5. Inspect for worn synchronizer key (2).
  6. Inspect for weak, damaged or broken spring (1).