1998 GMC Envoy Owner's Manual - Page 243

If You're Stuck: In Sand, Mud, Ice or Snow What you don't want to do when your vehicle is stuck is to spin your wheels too fast. The method known as "rocking" can help you get out when you're stuck, but you must use caution. NOTICE: Spinning your wheels can destroy parts of your vehicle as well as the tires. If you spin the wheels too fast while shifting your transmission back and forth,you can destroy your transmission. A CAUTION: If you let your tires spinat high speed, they can explode, and you or others could be injured. And, the transmission or other parts the vehicle can of overheat. That could cause an engine compartment fireor otherdamage. When you're stuck, spin the wheels as little as possible. Don't spin the wheels above 35 mph (55 km/h) asshown on the speedometer. I For information about using tire chains on your vehicle, see "Tire Chains" in the Index. 5-32