GM Full-Size Trucks 1988-1998 Repair Information

Manual Locking Hubs

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The engagement and disengagement of the hubs is a manual operation which must be performed at each hub assembly. The hubs should be placed FULLY in either Lock or Free position or damage will result.


WARNING
Do not place the transfer case in either 4-wheel mode unless the hubs are in the Lock position!

Locking hubs should be run in the Lock position periodically for a few miles to assure proper differential lubrication.

Removal & Installation

See Figure 1

This procedure requires snapring pliers. It cannot be performed properly without them!

  1. Raise and support the front end on jackstands.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the manual locking hubs

  1. Remove the wheels.
  2.  
  3. Lock the hubs. Remove the outer retaining plate, Allen head bolts and take off the plate, O-ring, and knob assembly.
  4.  

These bolts may have washers. Don't lose them!

  1. Remove the external snapring from the axle shaft.
  2.  
  3. Remove the compression spring.
  4.  
  5. Remove the clutch cup.
  6.  
  7. Remove the O-ring and dial screw.
  8.  
  9. Remove the clutch nut and seal.
  10.  
  11. Remove the large internal snapring from the wheel hub.
  12.  
  13. Remove the inner drive gear.
  14.  
  15. Remove the clutch ring and spring.
  16.  
  17. Remove the smaller internal snapring from the clutch hub body and remove the hub body.
  18.  
  19. Clean all hub parts in a safe, non-flammable solvent and wipe them dry.
  20.  
  21. Inspect each component for wear or damage. Make sure that the springs are functional and stiff. Make sure that all gear teeth are intact, with no chips or burrs.
  22.  
  23. Make sure that the splines on the inside of the wheel hub are clean and free of dirt, chips and burrs.
  24.  
  25. Surface irregularities can be cleaned up with light filing or emery paper.
  26.  
  27. Prior to assembly, coat all parts with the same wheel bearing grease you've used on the wheel bearings.
  28.  

To install:
  1. Install the hub body. Install the smaller internal snapring in the clutch hub body.
  2.  
  3. Install the clutch ring and spring.
  4.  
  5. Install the inner drive gear.
  6.  
  7. Install the large internal snapring in the wheel hub.
  8.  
  9. Install the external snapring on the axle shaft. If the snapring groove is not completely visible, reach around, inside the knuckle and push the axle shaft outwards.
  10.  
  11. Install the clutch nut and seal.
  12.  
  13. Install the O-ring and dial screw.
  14.  
  15. Install the clutch cup.
  16.  
  17. Install the compression spring.
  18.  
  19. Place the hub dial in the Lock position.
  20.  
  21. Coat the hub dial assembly O-ring with wheel bearing grease and position the hub dial and retainer on the hub.
  22.  
  23. Install the Allen head bolts. Make sure that you used any washers that were there originally. Tighten these bolts to 45 inch lbs. (5 Nm).
  24.  
  25. Rotate the hub dial to the free position and turn the wheel hubs to make sure that the axle is free.
  26.  
  27. Install the wheels.
  28.  

 
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