Visual/Physical Inspection
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, 2003 Chevrolet TrailBlazer, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.
Inspect the system for aftermarket devices which could affect the operation of the axle shafts. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.