2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 170

N (Neutral): In this position, the engine does not connect with the wheels. To restart when you are already moving, use N (Neutral) only. Also, use N (Neutral) when the vehicle is being towed. D (Drive): This position is for normal driving. It provides the best fuel economy. If you need more power for passing, and you are: . Going less than about 35 mph (55 km/h), push the accelerator pedal about halfway down. Going about 35 mph (55 km/h) or more, push the accelerator all the way down. By doing this, the vehicle shifts down to the next gear and has more power. { WARNING: Shifting into a drive gear while the engine is running at high speed is dangerous. Unless your foot is firmly on the brake pedal, the vehicle could move very rapidly. You could lose control and hit people or objects. Do not shift into a drive gear while the engine is running at high speed. Notice: Shifting out of P (Park) or N (Neutral) with the engine running at high speed may damage the transmission. The repairs would not be covered by the vehicle warranty. Be sure the engine is not running at high speed when shifting the vehicle. . D (Drive) can be used when towing a trailer, carrying a heavy load, driving on steep hills, or for off-road driving. You might want to shift the transmission to a lower gear selection if the transmission shifts too often. Downshifting the transmission in slippery road conditions could result in skidding. See Skidding under Loss of Control on page 5‑11. 3-32