2004 GMC Yukon Owner's Manual - Page 128

Shifting into 4LO To shift to the 4LO position, the ignition must be in RUN and the vehicle must be stopped or moving less than 3 mph (4.8 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting into 4LO is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the 4LO switch. You must wait for the 4LO indicator light to stop flashing and remain illuminated before shifting your transmission in gear. Notice: Shifting the transmission into gear before the 4LO indicator light has stopped flashing could damage the transfer case. To help avoid damaging your vehicle, always wait for the 4LO indicator light to stop flashing before shifting the transmission into gear. If the 4LO button is pressed when your vehicle is in gear and/or moving, the 4LO indicator light will flash for 30 seconds and not complete the shift unless your vehicle is moving less than 3 mph (4.8 km/h) and the transmission is in NEUTRAL (N). After 30 seconds the transfer case will return to the setting last chosen. When in 4LO, the vehicle stability is disabled. For more information see Stabilitrak® System on page 4-11. Shifting Out of 4LO To shift from 4LO to All-Wheel Drive your vehicle must be stopped or moving less than 3 mph (4.8 km/h) with the transmission in NEUTRAL (N) and the ignition in RUN. The preferred method for shifting out of 4LO is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the All-Wheel Drive button. You must wait for the AWD indicator light to stop flashing and remain illuminated before shifting your transmission into gear. If the All-Wheel Drive button is pressed when your vehicle is in gear and/or moving, the All-Wheel Drive indicator light will flash for 30 seconds but will not complete the shift unless your vehicle is moving less than 3 mph (4.8 km/h) and the transmission is in NEUTRAL (N). 2-34