PIT3078F

Bulletin No.: PIT3078F
Date: Oct-2012
Subject:
Grease Leak From Front Hub Bearings
Models:
2004-2013 Cadillac Escalade Models
2004-2013 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe
2004-2013 GMC Sierra, Sierra Classic, Yukon and Yukon Denali Models
2004-2010 Hummer H2
This PI was superseded to update model years and include photograph. Please discard PIT3078E.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
The factory grease fill of the front bearing/hub assembly exceeds the amount of grease that is required for adequate bearing lubrication throughout the life of the
vehicle. A portion of the grease will purge through the self-venting bearing seals for the initial drive period (a few thousand miles/kilometers) and helps to form
an additional barrier to block contamination of the bearing. This additional barrier is called a "grease dam". This grease dam will form in the area near the
bearing seal and will mix with outside dirt. In addition, grease may move radially outward from this area onto adjoining components, see example picture below.
Recommendation/Instructions
Do not replace the bearing for grease purge. Furthermore, do not clean the purged grease from the area immediately on or adjacent to the seals because this
grease provides additional protection. If desired, any grease that has migrated away from the immediate seal area can be wiped off.
The bearing should be replaced only if:
–
The seals show visible damage
–
The bearing endplay is greater than 0.005" or 0.13mm
–
The bearing exhibits rough rotation
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–
The bearing exhibits abnormal noise
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the
remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may
occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools,
safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that
your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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