Shift System Components

Tools Required 

J 22738-B  Valve Spring Tester. See Special Tools .

Fig 1: Identifying Shift System Components
Courtesy of GENERAL MOTORS CORP.
1. Clean the following shift system components in cleaning solvent and air dry:
   • The 2/4 synchronizer sleeve (224)
   • The 2/4 shift fork (243)
   • The control actuator shaft (261)
   • The high/low shift fork (258)
   • The control actuator cam (262)
   • The 2/4 synchronizer inserts (226) and springs (225)
   • The 2/4 synchronizer hub (227)
   • The 2/4 synchronizer rings (223, 222 and 221)
2. Inspect the control actuator cam (262) surfaces for the following conditions:
   • Roughness
   • Grooved
   • Excessive wear
3. Replace the control actuator cam if faulty.
4. Inspect the control actuator shaft (261) for the following conditions:
   • Wear at the seal surface
   • Actuator assembly engagement teeth stripped or excessively worn
5. Replace the control actuator shaft if faulty.
Fig 2: Measuring Synchronizer Wear With Feeler Gage
Courtesy of GENERAL MOTORS CORP.
6. Inspect the 2/4 synchronizer blocking ring (223) for chipped or worn engagement teeth.
7. Install the 2/4 synchronizer rings on the drive gear.
8. Using a feeler gage between the blocking ring teeth and the drive gear selector teeth, measure the synchronizer wear. Press down evenly on the rings while measuring.

   Specification: 

   • Standard clearance: 1.5 mm (0.059 in)
   • Minimum clearance: 0.8 mm (0.031 in)

Fig 3: Measuring Slots For Wear
Courtesy of GENERAL MOTORS CORP.
9. Measure the slots for the inserts, in the blocking ring (223), for wear.

   Specification:  Standard dimension: 9.5-9.7 mm (0.374-0.382 in)

10. Replace the 2/4 synchronizer rings if they are faulty.
Fig 4: Identifying Clearance Between Blocking Ring & Insert
Courtesy of GENERAL MOTORS CORP.
11. Using a vernier caliper, measure the clearance between the blocking ring and the insert.
12. If the measured value exceeds the specified limit, the blocking ring and the insert must be replaced.

    Specification: 

    • Standard blocking ring and insert clearance: 3.86-4.14 mm (0.152-0.163 in)
    • Limit blocking ring and insert clearance: 4.9 mm (0.193 in)

Fig 5: Checking 2/4 Synchronizer Hub For Wear
Courtesy of GENERAL MOTORS CORP.
13. Inspect the 2/4 synchronizer hub for the following conditions:
    • Splines (a) press fit to the rear output shaft
    • Steps worn in the sleeve teeth (b)
14. Install the inserts in the hub slots.
15. Using a feeler gage, measure for wear.

    Specification: 

    • Standard clearance: 0.01-0.19 mm (0.0004-0.0075 in)
    • Maximum clearance: 0.3 mm (0.012 in)

Fig 6: Locating 2/4 Synchronizer Sleeve Inspection Areas
Courtesy of GENERAL MOTORS CORP.
16. Inspect the 2/4 synchronizer sleeve for the following conditions:
    • Chipped or worn blocking ring teeth
    • Loose fit to the synchronizer hub caused by excessive wear
    • Shift fork collar surfaces for damage
17. Inspect the 2/4 synchronizer inserts for excessive wear.
18. Replace the 2/4 synchronizer assembly if any of the above conditions are found.
Fig 7: Identifying 2/4 Shift Shaft Inspection Areas
Courtesy of GENERAL MOTORS CORP.
19. Inspect the 2/4 shift shaft for excessive wear at the detent notches.
20. Inspect the 2/4 shift fork for excessive wear at the synchronizer sleeve surfaces.
21. Inspect the 2/4 shift fork for cracks or being bent.
22. Inspect the 2/4 shift fork shaft bore for excessive wear.
23. Replace any faulty or damaged components. Refer to Transfer Case Disassemble  and Transfer Case Assemble .
Fig 8: Expanded View Of High/Low Shift Shaft Inspection Points
Courtesy of GENERAL MOTORS CORP.
24. Inspect the high/low shift shaft for excessive wear at the detent notches.
25. Inspect the high/low shift block and collars for wear.
26. Replace any of the above components if they are found faulty. Refer to Transfer Case Disassemble  and Transfer Case Assemble .
Fig 9: Measuring Sleeve Pads
Courtesy of GENERAL MOTORS CORP.
27. Measure the sleeve pads on both shift forks for wear.

    Specification: 

    • 2/4 wheel drive shift fork standard thickness: 9.60-9.85 mm (0.378-0.388 in)
    • 2/4 wheel drive shift fork minimum thickness: 9.0 mm (0.354 in)
    • High/Low shift fork standard thickness: 7.60-7.85 mm (0.299-0.309 in)
    • High/Low shift fork minimum thickness: 7.0 mm (0.276 in)

28. If the measured value is less than the minimum thickness, replace the shift fork. Refer to Transfer Case Disassemble  and Transfer Case Assemble .
Fig 10: Vernier Caliper
Courtesy of GENERAL MOTORS CORP.
29. Inspect the detent springs for distortion or cracks.
30. Measure the detent spring free length.

    Specification: 

    • Standard length: 23.4 mm (0.92 in)
    • Minimum length: 23.1 mm (0.91 in)

31. Measure the inner range shift detent spring free length.

    Specification: 

    • Standard length: 26.6 mm (1.05 in)
    • Minimum length: 25.6 mm (1.01 in)

Fig 11: Identifying J 22738-B
Courtesy of GENERAL MOTORS CORP.
32. Use J 22738-B  or equivalent to measure the detent spring tension. See Special Tools .

    Specification: 

    • Compressed height: 18.7 mm (0.736 in)
    • Standard tension: 7.5-8.5 kg (16.5-18.7 lb)

33. Use J 22738-B  or equivalent to measure the inner range shift detent spring tension. See Special Tools .

    Specification: 

    • Compressed height: 18.7 mm (0.736 in)
    • Standard tension: 3.3-4.3 kg (7.3-9.5 lb)

34. Replace the detent springs if found faulty.