2005 GMC Envoy Owner's Manual - Page 103

If the lights do not come on, you should take your vehicle to your dealer for service. An indicator light will flash while shifting the transfer case. It will stay on when the shift is complete. If for some reason the transfer case cannot make a requested shift, it will return to the last chosen setting. If the service four-wheel drive light on the instrument panel cluster stays on, you should take your vehicle to your dealer for service. See Service Four-Wheel Drive Warning Light on page 3-47 for further information. Turn the knob to 4LO. You must wait for the 4LO indicator light to stop flashing and stay on before shifting the transmission into gear. If you turn the knob to 4LO 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 2 mph (3.2 km/h) and the transmission is in NEUTRAL (N). After 30 seconds, the transfer case will return to the setting last chosen. Shifting Into 4HI (Four-Wheel High) or A4WD (Automatic Four-Wheel Drive) Turn the knob to 4HI or A4WD. This can be done at any speed unless you are shifting out of 4LO. The indicator light will flash while shifting. It will remain on when the shift is complete. Shifting Out of 4LO (Four-Wheel Low) To shift from 4LO to 4HI, A4WD drive, or 2HI your vehicle must be stopped or moving less than 2 mph (3.2 km/h) with the transmission in NEUTRAL (N) and the engine running. The preferred method for shifting out of 4LO is to have your vehicle moving 1 or 2 mph (1.6 to 3.2 km/h). Turn the knob to 4HI, A4WD or 2HI. You must wait for the 4HI, A4WD, or 2HI indicator light to stop flashing and stay off before shifting your transmission into gear. If the knob is turned to 4HI, A4WD, or 2HI when your vehicle is in gear and/or moving, the 4HI, A4WD, or 2HI indicator light will flash for 30 seconds. It will not complete the shift unless your vehicle is moving less than 2 mph (3.2 km/h) with the transmission in NEUTRAL (N). Shifting Into 2HI (Two-Wheel High) Turn the knob to 2HI. This can be done at any speed unless you are shifting out of 4LO. Shifting Into 4LO (Four-Wheel Low) To shift to 4LO, the vehicle's engine must be running and the vehicle must be stopped or moving less than 2 mph (3.2 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting into 4LO is to have your vehicle moving 1 or 2 mph (1.6 to 3.2 km/h). 2-29