Diagnostic Aids
WARNING: This page is about a different car, the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
A mechanical condition inside the front axle could prevent the shift fork from moving causing the motor to be stuck in one position. Refer to Symptoms - Front Drive Axle .