One problem related to rear axle spindle has been reported for the 2003 Chevrolet Silverado. The most recently reported issues are listed below.
Both rear axle seals leaked and grease was coming out and getting on the end of the axles and on the rear rotor disc brakes. When braking heavy on hills smoke eminated, mostly on the left side. Mechanic was on vacation and consumer was waiting mechanic's return for repairs. Consumer did contact gm, who said they had no reports on this issue, but there was a recall on the rear brakes. Consumer had an appointment, and dealer stated they would look into axles when repairing the recall.