GM Service Manual Online
For 1990-2009 cars only

Self-Adjusting

The self-adjusting rear suspension may come as part of the premium smooth ride suspension package.

This type of level control will provide a leveled riding position as well as improved handling under a variety of passenger and loading conditions. A hydraulic pump inside each rear shock absorber raises the rear of the vehicle to the proper height, based on inputs from the road surface, while the vehicle is being driven. It take approximately 2 miles (3.2 km) of driving for the leveling to complete, depending on the road surface conditions.

If the loaded vehicle is not moved for approximately 12 hours, the leveling system may bleed down to a lower height. This can be especially apparent if a trailer is left attached to a parked vehicle for long periods of time. The vehicle must be driven to re-level the vehicle.

If a self-equalizing hitch is being used, the vehicle should be driven approximately 2 miles (3.2 km) with the trailer prior to adjusting (leveling) the hitch.