2003 GMC Sierra 1500 Pickup Owner's Manual - Page 124

NEUTRAL (N): Shift to this setting only when your vehicle needs to be towed. The ignition switch must be in RUN in order to shift the lever into NEUTRAL (N). See Recreational Vehicle Towing on page 4-53 or Towing Your Vehicle on page 4-53. 4-Wheel Low (4LO): This setting also engages your front axle and delivers extra torque. You may never need 4LO. It sends maximum power to all four wheels. You might choose 4LO if you are driving off-road in deep sand, deep mud, deep snow and climbing or descending steep hills. You can shift from 2-Wheel High (2HI) to 4-Wheel High (4HI) or from 4-Wheel High (4HI) to 2-Wheel High (2HI) while the vehicle is moving. Your front axle will engage faster if you take your foot off of the accelerator for a couple of seconds after you shift. In extremely cold weather, it may be necessary to stop or slow the vehicle to shift into 4-Wheel High (4HI). Don't pause in NEUTRAL (N) as you shift the transfer case into 4 Wheel Low (4LO), or your gears could clash. Remember that driving in 4-Wheel High (4HI) or 4-Wheel Low (4LO) may reduce fuel economy. Also, driving in four-wheel drive on dry pavement could cause your tires to wear faster and make your transfer case harder to shift and run noisier. Automatic Transfer Case The transfer case buttons are located to the left of the instrument panel cluster. To shift into or out of 4-Wheel Low (4LO) or NEUTRAL (N): 1. Slow the vehicle to a roll, about 1 to 3 mph (2 to 5 km/h) and shift an automatic transmission into NEUTRAL (N), or with a manualtransmission, press the clutch pedal. Use these switches to shift into and out of four-wheel drive. 2. Shift the transfer case shift lever in one continuous motion. 2-37