WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo and 2002 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Noise In Steering Column Diagnosis (1 Of 2)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Noise In Steering Column Diagnosis (2 Of 2)