Hummer H2. Manual - part 879

wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after 
assembly. 

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Lubricate the bearings with axle lubricant. Inspect the bearings for smooth rotation.  

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Inspect the bearing rollers for wear.  

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Inspect the bearing cups for wear, cracks, brinelling, and scoring.  

PINION AND RING GEAR INSPECTION 

Ring and pinion gears are matched sets. When replacement of one or the other is necessary, both the ring and 
pinion gear must be replaced. 

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Check the pinion and ring gear teeth for cracking, chipping, scoring, or excessive wear.  

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Check the pinion gear splines for wear.  

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Check the pinion flange/yoke splines for wear.  

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Check the fit of the pinion gear splines on the pinion flange/yoke.  

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Check the sealing surface of the pinion flange/yoke for nicks, burrs or rough tool marks that could 
damage the seal and cause an oil leak.  

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Check for worn or broken parts and replace as necessary.  

REAR AXLE HOUSING INSPECTION 

Carefully and thoroughly inspect all drive unit parts before assembly. Thorough inspection of the drive parts for 
wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after 
assembly. 

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Inspect for nicks or burrs that could prevent the outer diameter of the pinion seal from sealing. Remove 
any burrs.  

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Inspect the bearing cup bores for nicks or burrs. Remove any burrs that are found.  

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Inspect the housing for cracks. Replace the housing if any cracks are found.  

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Inspect the housing for foreign material such as metal chips, dirt, or rust.  

SHIMS INSPECTION 

Inspect the shims for cracks and chips. Replace the damaged shims.

IMPORTANT: The differential bearings and the bearing cups are matched sets. Replace 

both the bearing and the cup when either part requires replacement.

IMPORTANT:

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Do not reinstall the original cast iron production shims, if removed. Once 
the cast iron shims are removed from the axle housing, they must be 
replaced with service shims and spacers.  

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If service shims were previously installed, the shims can be reused.  

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Rear Drive Axle - Hummer H2

  

PINION DEPTH ADJUSTMENT 

Tools Required 

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J 21777-85 Gauge and Plate. See Special Tools and Equipment .  

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J 21777-86 Side Bearing Disc, 2 Required. See Special Tools and Equipment .  

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J 34925 Pinion Setting Gauge and Components  

1. Lubricate the pinion bearings with axle lubricant. Use the proper fluid. Refer to Fluid and Lubricant 

Recommendations in Maintenance and Lubrication. 

IMPORTANT: Make sure all of the tools, the differential side bearing bores, and the 

pinion bearing cups are clean before proceeding.

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Rear Drive Axle - Hummer H2

  

Fig. 110: Assembling J 21777-35, J 21777-43, J 21777-42 & J 45230 
Courtesy of GENERAL MOTORS CORP. 

2. Assemble the following components into the axle housing: 

1. Install the pinion bearings into the axle housing.  

2. Assemble the J 21777-8 (1), the J 21777-43 (2), the J 21777-42 (3), and the J 21777-85 (4) as 

shown.  

3. While holding the J 21777-43 stationary, slowly tighten the nut of the J 21777-43 until a rotating torque 

of approximately 1.1-2.2 N.m (10-20 lb in) is obtained.  

4. Rotate the assembly several times in both directions in order to seat the pinion bearings.  

5. Measure the rotating torque of the assembly using an inch-pound torque wrench. 

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Rear Drive Axle - Hummer H2

  

Specification: The rotating torque of the assembly should be 1.1-2.3 N.m (10-20 lb in). 

6. If the rotating torque of the assembly is less than 1.1 N.m (10 lb in), continue to tighten the nut on the J 

21777-43 until a rotating torque of 1.1-2.3 N.m (10-20 lb in) is obtained. 

Fig. 111: Assembling J 21777-86 To J 21777-1 
Courtesy of GENERAL MOTORS CORP. 

7. Assemble the J 21777-86 (1, 2) to the J 21777-1 (3) and install into the differential carrier bore of the axle 

housing as shown.  

8. Install the bearing caps. 

NOTE:

Refer to Fastener Notice in Cautions and Notices.

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Rear Drive Axle - Hummer H2