2003 GMC Sierra 1500 Pickup Owner's Manual - Page 125

Recommended Transfer Case Settings I [M (4HI): Use 4HI when you need extra traction, such ' ) a on snowy or icy roads or in most off-road situations. This setting also engages your front axle to help drive your vehicle. This is the best setting to use when plowing snow. (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. I Driving Conditions Normal Variable Severe Vehicle in Tow* I lAuTo I YES I I I I Transfer Case Settings 4HI 4LO N 2HI 4WD YES YES YES YES *See "Recreational Vehicle Towing" in the Index for further information. You can choose among four driving settings: (2HI): This setting is used for driving in most street and highway situations. Your front axle is not engaged in two- wheel drive. This setting also provides the best fuel economy. AUTO 4WD: This setting is ideal for use when road conditions are variable. When driving your vehicle in AUTO 4WD, the front axle is engaged, but the vehicle's power is sent to the rear wheels. When the vehicle senses a loss of traction, the system will automatically engage four-wheel drive. Driving in this mode results in slightly lower fuel economy than 2HI. Shifting the transfer case EUTRAL 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" in the Index. 2-38