Differential Unit problems of the 2003 GMC Sonoma

It has been determined that water has contaminanted the oil in the rear differential causing a mechanical failure. I have been informed that my extended warranty does not cover this issue even though GMC is aware that problem with a vent tube location is one source for water infiltration. I have a GMC document with specific instructions for mechanics to check for the improper vent tube location if water is indeed found in the rear axle fluid.

Contact states above the rear end differential there is a vent tube placed between where the truck bed stops and the cap starts, and there is about 1 -1/2 inch space left between. This space lets water collect, running down the tube, destroying the oil, and causing the lubrication on the rear end differential to be destroyed. A technical service bulletin for September 2004 discusses the same component. The rear seal had blown out which caused grease to escape. The consumer was told the entire rear end including the axle bearing and seals had to be replaced.

The contact owns a 2003 GMC Sonoma. In June of 2004, the differential was failing and the paint was deteriorating on the vehicle. The contact attempted to repair the vehicle himself, but the part was unavailable. The manufacturer advised him to have the vehicle diagnosed. The contact feels that the part should be available and is not willing to pay for a diagnostic. The failure mileage was 45,000 and current mileage was 65,000. Updated 5/14/09 updated 05/14/09.