2001 GMC Yukon Owner's Manual - Page 112

Level Control (If Equipped) CAUTION: It can be dangerous to get out of your vehicle if the shift lever is not fully in PARK (P) with the parking brake firmly set. Your vehicle can roll. Don't leave your vehicle when the engine is running unless you have to. If you've left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure your vehicle won't move, even when you're on fairly level ground, always set your parking brake and move the shift lever to PARK (P). Four-wheel drive vehicles with the transfer case in NEUTRAL will allow the vehicle to roll, even if your shift lever is in PARK (P). So, be sure the transfer case is in a drive gear -- not in NEUTRAL. Always set your parking brake. Follow the proper steps to be sure your vehicle won't move. See "Shifting Into PARK (P)" in the Index. If you're pulling a trailer, see "Towing a Trailer" in the Index. Self-Adjusting The self-adjusting rear suspension is available on C/K 1500 vehicles and is available with 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 takes 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 twelve 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. 2-34