2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 183

2 m (Two-Wheel-Drive High): This setting is used for driving in most street and highway situations. The front axle is not engaged in Two-Wheel Drive. This setting also provides the best fuel economy. 4 m (Four-Wheel-Drive High): Use the Four-Wheel-Drive High position when extra traction is needed, such as on snowy or icy roads or in most off-road situations. This setting also engages the front axle to help drive the vehicle. This is the best setting to use when plowing snow. 4 n (Four-Wheel-Drive Low): This setting also engages the front axle and delivers extra torque. You may never need this setting. It sends maximum power to all four wheels. You might choose Four-Wheel-Drive Low while driving off-road in deep sand, deep mud, deep snow, and while climbing or descending steep hills. If the vehicle has StabiliTrak®, shifting into Four-Wheel-Drive Low will turn Traction Control and StabiliTrak® off. See StabiliTrak® System on page 5‑6. { WARNING: Shifting the transfer case to N (Neutral) can cause the vehicle to roll even if the transmission is in P (Park). You or someone else could be seriously injured. Be sure to set the parking brake before placing the transfer case in N (Neutral). See Parking Brake on page 3‑54. N (Neutral): Shift the vehicle's transfer case to N (Neutral) only when towing the vehicle. See Recreational Vehicle Towing on page 5‑49 or Towing Your Vehicle on page 5‑48 for more information. If the SERVICE 4-WHEEL DRIVE message stays on, you should take the vehicle to your dealer for service. See "Service 4-Wheel Drive message" under DIC Warnings and Messages on page 4‑66. 3-45