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Perceived Fluid Leak at Rear Seal - keywords prop shaft yoke

Subject:Perceived Fluid Leak at Rear Seal

Models:2008 Chevrolet Avalanche, Suburban, Tahoe
2007-2008 Chevrolet Silverado
2007-2008 GMC Sierra
2008 GMC Yukon, Yukon XL
Equipped with Magna Transfer Case RPO Codes NQF, NQG, NQH



This PI was superceded to update models and years. Please discard PIP4127.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some dealers may notice during PDI inspection that a small amount of transfer case oil is visible around the rear output seal.

Some dealers have recently replaced seals for this condition. These seals that were thought to be defective at PDI. The seals were actually not defective.

Recommendation/Instructions:

All transfer cases arrive at the plants with a shipping plug inserted into the rear output. This shipping plug goes through the rear output seal. As the shipping plug is removed a small amount of oil that has built up in behind the plug is released. While some fluid leakage does occur at shipping plug removal, this condition should not be diagnosed as a defective seal.

If some seepage of residual oil is apparent at the rear output seal during PDI inspection the technician should carefully wipe it off and dry the surface with a clean shop cloth. If seal leakage is apparent after being thoroughly cleaned to a point where it drips onto the ground then the seal should be replaced before the customer takes delivery.

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.