2009 GMC Envoy Owner's Manual - Page 104

To shift to the 3 (Third) position, you must first press the large button on the shift handle. While the button is pressed, move the shifter in the 3 (Third) position. 2 (Second): This position reduces vehicle speed even more than 3 (Third) without using the brakes. You can use 2 (Second) on hills. It can help you control vehicle speed as you go down steep mountain roads, as you use your brakes off and on. To shift to the 2 (Second) position, you must first press the large button on the shift handle. While the button is pressed, move the shifter in the 2 (Second) position. You can also use 2 (Second) for starting the vehicle from a stop on slippery road surfaces. 1 (First): This position reduces vehicle speed even more than 2 (Second) without using the brakes. You can use it on very steep hills, or in deep snow or mud. If the shift lever is put in 1 (First) while the vehicle is moving forward, the transmission will not shift into first gear until the vehicle is going slowly enough. To shift to the 1 (First) position, you must first press the large button on the shift handle. While the button is pressed, move the shifter in the 1 (First) position. Notice: Spinning the tires or holding the vehicle in one place on a hill using only the accelerator pedal may damage the transmission. The repair will not be covered by the vehicle warranty. If you are stuck, do not spin the tires. When stopping on a hill, use the brakes to hold the vehicle in place. Four-Wheel Drive If the vehicle has four-wheel drive, the engine's driving power can be sent to all four wheels for extra traction. Read the following before using four-wheel drive, to become familiar with its operation. You should use Two-Wheel High for most normal driving conditions. Notice: Driving on clean, dry pavement in Four-Wheel-Drive High or Four-Wheel-Drive Low for an extended period of time may cause premature wear on your vehicle's powertrain. Do not drive on clean, dry pavement in Four-Wheel-Drive High or Four-Wheel-Drive Low for extended periods of time. Notice: If you continually drive your vehicle with the transfer case in AUTO or Four-Wheel Drive, you could shorten the life of the transfer case or the Four-Wheel Drive system. The selector switch should be left in Two-Wheel Drive High mode. Only use AUTO and Four-Wheel Drive when you need extra traction such as in wet or slippery road conditions. 2-28