1998 GMC Envoy Owner's Manual - Page 81

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. I f the selector lever is put in FIRST (1) while the vehicle is moving forward, the transmission won't shift into FIRST (1) until the vehicle is going slowly enough. Parking Brake To set the parking brake. hold the regular brake pedal down with your right foot. Push down the parking brake pedal with your left foot. If the ignition is on, the brake system warning light will come on. To release the parking brake, hold the regular brake pedal down. NOTICE: If your rear wheels can't rotate, don't try to drive. This might happen you were stuckin if very deep sand or mud or were up against a solid object. You could damage your transmission. Also, if you stop when going uphill, don't hold your vehicle there with only the accelerator pedal. This could overheat and damage the transmission. Use your brakes or shift into PARK (P) to hold yourvehicle in position on a hill. Pull the BRAKE RELEASE lever. It is located on the bottom of the driver's side of the instrument panel. 2-20