1997 GMC Safari Owner's Manual - Page 96

FIRST (1): This position gives you even more power (but lower fuel economy) than SECOND ( 2 ) .You can use it on very steep hills, or in deep snow or mud. If the selector leveris put in FIRST (l), the transmission won't shift into first gear until the vehicle is going slow enough. Locking Rear Axle If you have this feature, your 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, the locking feature will allow the wheel with traction to move the vehicle. I NOTICE: If your rear wheels can't rotate, don't try to drive. This might happen if you were stuck in very deepsand or mud or were up againsta solid object. You could damage your transmission or transfer case or both. Also, if you stop when going uphill, don't hold your vehicle there with only the accelerator pedal. This could overheat anddamage the transmission. Use your brakes or shift into PARK (P) to hold your vehicle in position on a hill. All-Wheel Drive (Option) If your vehicle has all-wheel drive, your engine's driving power is sent to all four wheels for extratraction. This is like four-wheel drive, but there is no separate lever orswitch to engage or disengage the frontaxle. It is fully automatic, and adjusts itself as needed for road conditions.