One problem related to steering gear box has been reported for the 2003 Chevrolet Avalanche. The most recently reported issues are listed below.
The steering gear box appears to be loose, vehicles under warranty are getting repaired but those out of warranty are not. When I had the tailgate hinges replaced, the dealer explained what was wrong with my truck but could not repair it. It's a nerve racking vibration which should be taken care of and feels like the left front wheel assemblt is about to fall off.