2007 GMC Sierra 1500 Pickup Owner's Manual - Page 165

{CAUTION: Shifting the transfer case to NEUTRAL can cause your vehicle to roll even if the transmission is in PARK (P). You or someone else could be seriously injured. Be sure to set the parking brake before placing the transfer case in NEUTRAL. See Parking Brake on page 169. (N) NEUTRAL: Shift the vehicle's transfer case to NEUTRAL only when towing your vehicle. See Recreational Vehicle Towing on page 424 or Towing Your Vehicle on page 423 for more information. 4 m (Four-Wheel Drive High): This setting engages the front axle to help drive your vehicle. Use Four-Wheel Drive High when you need extra traction, such as on snowy or icy roads, or in most off-road situations. 4 n (Four-Wheel Drive Low): This setting also engages your front axle to give you extra traction. You may never need Four-Wheel Drive Low. It sends the maximum power to all four wheels. You might choose Four-Wheel Drive Low if you were driving off-road in sand, mud or deep snow and while climbing or descending steep hills. When operating in Four-Wheel Drive Low, the gear ratio provides additional torque when compared to Four-Wheel Drive High. The transmission gear shift feel will be exaggerated. Shifting from Two-Wheel Drive High to Four-Wheel Drive High Press and release the Four-Wheel Drive High switch. This can be done at any speed. The front axle will lock automatically with some delay. Shifting from Four-Wheel Drive High to Two-Wheel Drive High Press and release the Two-Wheel Drive High switch. This can be done at any speed. The front axle will unlock automatically with some delay. 165