GM Service Manual Online
For 1990-2009 cars only

First, turn your steering wheel left and right. That will clear the area around your front wheels. If your vehicle has traction control, you should turn the system off. See Traction Control System (TCS) . Then shift back and forth between REVERSE (R) and a forward gear, or with a manual transaxle, between FIRST (1) or SECOND (2) and REVERSE (R), spinning the wheels as little as possible. Release the accelerator pedal while you shift, and press lightly on the accelerator pedal when the transaxle is in gear. By slowly spinning your wheels in the forward and reverse directions, you will cause a rocking motion that may free your vehicle. If that does not get you out after a few tries, you may need to be towed out. Or, you can use the recovery hook if your vehicle has one. If you do need to be towed out, see Towing Your Vehicle .

Vehicles Equipped with VTi Variable Transmission

If you press too hard on the accelerator pedal, you may not be able to shift into DRIVE (D) or REVERSE (R). If this happens, release the accelerator pedal, then shift to the gear you want.