1997 GMC Sonoma Owner's Manual - Page 66

Ensure the shift lever is fully in PARK (P) range before starting the engine. Your vehicle has a brake-transmission shift interlock. You have to fully apply your regular brakes before you can shift from PARK (P) when the ignition key is in the RUN position. If you cannot shift out of PARK (P), ease pressure on the shift lever -- push the shift lever all the way into PARK (P) as you maintain brake application. Then move the shift lever into the gear you wish. See "Shifting Out of PARK (P)" in the Index. REVERSE (Rj: Use this gear to back up. NEUTRAL (N): In this position, your engine doesn't connect with the wheels. To restart when you're already moving, use NEUTRAL (N) only. NOTICE: Shifting to REVERSE (R) while your vehicle is moving forward could damage your transmission. Shift to REVERSE (R) only after your vehicle is stopped. To rock your vehicle back and forth to get out of snow, ice or sand without damaging your transmission, see "Stuck in Sand, Mud, Ice or Snow" in the Index. Shifting outof PARK (P) or NEUTRAL (N) while your engineis "racing" (running at high speed) is dangerous. Unless your foot is firmly on the brake pedal, your vehicle could movevery rapidly. You could lose control and hit people or objects. Don't shift out PARK (P) or of NEUTRAL (N) while your engineis racing. I NOTICE: Damage to your transmission caused shifting by out of PARK (P) or NEUTRAL (N) with the engine racingisn't covered by your warranty. 2-18