Hummer H2. Manual - part 910

Fig. 24: Frettage 
Courtesy of GENERAL MOTORS CORP. 

Corrosion set up by a small relative movement of parts with no lubrication. Replace the bearing. Clean all the 
relative parts. Check the seals. Check for proper fit and lubrication. Replace the shaft if damaged. 

Smears 

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Front Drive Axle - Hummer H2

  

Fig. 25: Smears 
Courtesy of GENERAL MOTORS CORP. 

Smearing of metal due to slippage. Slippage can be caused by poor fits, lack of lubrication, overheating, 
overloads or handling damage. Replace the bearing. Clean all the related parts. Check for proper fit and 
lubrication. 

FRONT AXLE LUBRICANT LEAK DIAGNOSIS 

Front axle lubricant leaks can occur at the following locations: 

z

Axle shaft oil seals  

z

Differential carrier assembly mating surface 

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Front Drive Axle - Hummer H2

  

z

Drain plug  

z

Fill plug  

z

Inner axle tube assembly to differential carrier assembly mating surface  

z

Pinion yoke oil seal  

z

Vent tube  

Determining the Cause 

While most front axle leaks may be easy to find, determining the cause may not be. A thorough inspection of 
the area around the leak may assist in determining the cause of the leak. 

Oil Seals 

Lubricant leaks from a oil seal may be caused by any of the following: 

z

An improperly installed seal  

z

A distorted seal  

z

A worn seal  

z

A worn shaft  

z

A brittle seal lip  

z

A hardened seal lip  

To determine the actual cause of the leak, clean the area around the leak. Observe the area of the leak and 
determine the if the seal or another component is causing the leak. A worn seal surface will cause a leak at the 
sealing lip while a misaligned seal or a seal installed into a housing with an excessive bore will cause the seal to 
leak at the outside surface of the seal. Hardened or cracked seal lips usually indicate the axle is operating 
beyond the normal temperature limits for the axle. A seal whose sealing surface has been nicked or cut may 
indicate that the shaft has a rough, burred, or gouged surface and will need to be inspected before the seal can 
be replaced. 

Sealing Surfaces 

Front axles components are assembled using specific sealers. A leak at a surface sealed with sealant is usually 
caused by a poor fit of the components but can also be caused by the use of the wrong sealant. When correcting 
a sealant leak, inspect each component for distortion and for nicks or gouges that may prohibit the sealant from 
sealing properly and when re-assembling the component, use the proper sealant. 

Differential Carrier Assembly 

Lubricant leaks at the differential carrier assembly can occur at the following locations: 

z

Drain Plug  

z

Fill Plug  

z

Vent tube  

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Front Drive Axle - Hummer H2

  

Drain and fill plug leaks are usually caused by a loose plug. A vent tube leak can be cause by a loose fitting 
vent hose or by a vent tube assembly whose interior shield is stuck in the upside down position. Inspect the vent 
plug's interior shield for unrestricted movement, repair or replace the plug as necessary. Drain or fill plug leaks 
can be repaired by either tightening the plug or by using an approved sealer on the threads on the plug. 

REPAIR INSTRUCTIONS 

LUBRICANT LEVEL INSPECTION - FRONT DRIVE AXLE 

1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.  

2. Make sure the vehicle is level.  

3. Inspect the front axle for leaks. Repair as necessary.  

4. Remove the engine protection shield (if equipped). Refer to Engine Protection Shield Replacement in 

Frame and Underbody.  

5. Clean the area around the front axle fill plug (1). 

Fig. 26: Front Drive Axle Fill & Drain Plug

 

2004 Hummer H2 

2004 DRIVELINE/AXLE Front Drive Axle - Hummer H2