1999 GMC Suburban Owner's Manual - Page 93

yellowblue Shifting to 4HI or AUTO 4WD CAUTION: Shifting the transfer case to NEUTRAL 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. NEUTRAL: Shift the vehicle's transfer case to neutral only when towing your vehicle. See "Recreational Vehicle Towing" or "Towing Your Vehicle" in the Index for more information. Indicator lights in the switches show which setting you are in. The indicator lights will come on briefly when you turn on the ignition and one will stay on. 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 remain illuminated 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 4WD light stays on, you should take your vehicle to your dealer for service. See "Service 4WD" in the Index for further information. Press and release the 4HI or AUTO 4WD switch. This can be done at any speed, and the indicator light will flash while shifting. It will remain illuminated when the shift is completed. Shifting to 2HI Press and release the 2HI switch. This can be done at any speed. Shifting to 4LO To shift to 4LO, the vehicle's engine must be running 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 into gear. If the 4LO switch 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. 2-23