2007 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 161

Shifting into Four-Wheel Drive Low Notice: Shifting the transfer case into Four-Wheel Drive Low while moving at speeds faster than 3 mph (5 km/h) may cause premature wear to the transfer case, and may cause the gears to grind. To avoid causing premature wear, and grinding the gears, do not shift the transfer case into Four-Wheel Drive Low while the vehicle is moving faster than 3 mph (5 km/h). To shift to Four-Wheel Drive Low, the ignition must be in RUN and the vehicle must be stopped or moving less than 3 mph (5 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting into Four-Wheel Drive Low is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the Four-Wheel Drive Low switch. You must wait for the Four-Wheel Drive Low indicator light to stop flashing and remain on before shifting the transmission into gear. Notice: Shifting the transmission into gear before the Four-Wheel Drive Low indicator light has stopped flashing could damage the transfer case. To help avoid damaging your vehicle, always wait for the Four-Wheel Drive Low indicator light to stop flashing before shifting the transmission into gear. It is typical for your vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from NEUTRAL (N) with the engine running. If the Four-Wheel Drive Low switch is pressed when your vehicle is in gear and/or moving, the Four-Wheel Drive Low indicator light will flash for 30 seconds and the vehicle will not complete the shift unless it is moving less than 3 mph (5 km/h) and the transmission is in NEUTRAL (N). After 30 seconds the transfer case will shift to Four-Wheel Drive High mode. 161