1993 Buick Riviera Owner's Manual - Page 216

If You're Stuck: In Sand, Mud, Ice or Snow What you don't want do when your vehicleis stuck is to as to spin your wheels. The method known "rocking" can helpyou get out when you're stuck, but you must use caution. A CAUTION: If you let your tires spin at high speed, they can explode and you or others could be injured. And, the transaxle or other parts of the vehicle can overheat. Thatcould cause an engine compartment fire or other damage. Whenyou're stuck, spin the wheels as little as possible. Don't spin the wheels above35 mph (55 km/h) as shown on the speedometer. I L