Hummer H2. Manual — part 954

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

Courtesy of GENERAL MOTORS CORP.

6. Remove the front axle fill plug (1).

7. Inspect the oil level.

Specification: The oil level should be between 0-10 mm (0-0.375 in) below the fill plug opening.

8. If the level is low, add oil until the level is even with the bottom edge of the fill plug opening. Use the

proper fluid. Refer to Fluid and Lubricant Recommendations in Maintenance and Lubrication.

9. Install the fill plug.

Tighten: Tighten the plug to 33 N.m (24 lb ft).

10. Install the engine protection shield. Refer to Engine Protection Shield Replacement in Frame and

Underbody.

11. Lower the vehicle.

LUBRICANT REPLACEMENT - FRONT DRIVE AXLE

Removal Procedure

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

NOTE:

Refer to Fastener Notice in Cautions and Notices.

2004 Hummer H2

2004 DRIVELINE/AXLE Front Drive Axle - Hummer H2