2003 Chevrolet Avalanche Owner's Manual - Page 107

Four-wheel Drive If your vehicle has four-wheel drive, you can send your engine's driving power to all four wheels for extra traction. To get the most satisfaction out of four-wheel drive, you must be familiar with its operation. Read the part that follows before using four-wheel drive. See the appropriate text for the transfer case in your vehicle. Notice: Driving in the 4-WHEEL HIGH (4HI) or 4-WHEEL LOW (4LO) positions for a long time on dry or wet pavement could shorten the life of your vehicle's drivetrain. Front Axle Locking Feature The front axle locks and unlocks automatically when you shift the transfer case. Some delay for the axle to lock or unlock is normal. Automatic Transfer Case I I Shifting the tr,..sfer case to NEUTRAL can cause your vehicleto 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. 2-34