2003 GMC Sonoma Owner's Manual - Page 100

Make sure the shift lever is fully in PARK (P) before starting the engine. Your vehicle has an automatic transmission shift lock control system. You have to fully apply your regular brakes before you can shift from PARK (Pj when the ignition key is in RUN. 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) on page 2-34. REVERSE (R): Use this gear to back up. Notice: Shifting to REVERSE (R) while your vehicle is moving forward could damage your transmission. Shift to REVERSE (R) only after your vehicleis stopped. To rock your vehicle back and forth to get out of snow, ice or sand without damaging your transmission, see If You Are Stuck: In Sand, Mud, Ice or Snow on page 4-42. NEUTRAL (N): In this position, your engine doesn't connect with the wheels. To restart when you're already moving, use NEUTRAL (N) only. Shifting into a drive gear while your engine is "racing" (running at high speed) is dangerous. Unless your foot is firmly on the brake pedal, your vehicle could move very rapidly. You could lose control and hit people or objects. Don't shift into a drive gear while your engine is racing. Notice: Damage to your transmission caused by shifting out of PARK (P) or NEUTRAL (N) with the engine racing isn't covered by your warranty. 2-25