One problem related to differential unit has been reported for the 2003 Chevrolet Avalanche. The most recently reported issues are listed below.
At a regular service interval, the Chevrolet dealership informed me the front differential has a bad seal and needs to be replaced. This seems premature since the vehicle only has 34,000 miles on it. The dealer stated it was not a warranty repair due to time elapsed since purchased was over 36 months.