1998 GMC Sonoma Owner's Manual - Page 92

Locking Rear Axle (If Equipped) It can be dangerous to getofout vehicle if your the shift lever not fully in PARK (P) with the is parking brake firmlyset. Your vehicle can roll. Don't leave yourvehicle when the engineis running unlessyou have to. If you've left the engine running, the vehicle can move suddenly. You or others could injured. To be sure your be vehicle won't move, even when you're onfairly level ground, always set your parking brake and move the shift lever to PARK (P). If you have this feature, your locking rear axle can give you additional traction on snow, mud, ice, sand or gravel. It works like a standard axle most of the time, but when one of the rear wheels has no traction and the other does, this feature will allow the wheel with traction to move the vehicle. ~ Four-wheel Drive (If Equipped) If your vehicle has four-wheel drive, you can send your engine's driving power to all four wheels for extra traction. To shift out of two-wheel drive and into four-wheel drive, push the 4HI or 4LO on the transfer case swit.ch.You should use 2HI for most ngrmal driving conditions. Follow the proper steps to be sure your vehicle won't move. See "Shifting Into PARK (P)" in the Index. I If you're pulling a trailer, see "Towing a Trailer" in the Index. NOTICE: Driving in the 4HI or 4LO positions fora long time on dry or pavement could shorten the wet life of your vehicle's drivetrain. 2-28