2008 GMC Sierra 1500 Pickup Owner's Manual - Page 107

Tow/Haul Mode See Tow/Haul Mode Light on page 3-50 for more information. Also see "Tow Haul Mode" under Towing a Trailer on page 4-41 for more information. Grade Braking Grade Braking assists when driving on a downhill grade. It maintains the vehicle's speed by automatically using a shift schedule that lets the engine and the transmission slow the vehicle. This reduces wear on the brakes system and increases control of the vehicle. The system constantly monitors the vehicle's speed, acceleration, throttle position, and whether the brake pedal is being pressed, and determines when to keep the current vehicle speed or to slow down. The system then automatically, commands downshifts that reduce the vehicles speed, until the brake pedal is no longer being pressed. This indicates the desired vehicle speed has been reached. The tow/haul mode and grade braking shift modes can be activated by pressing the button on the end of the shift control stalk. While in the Range Selection Mode, grade braking is deactivated, and lets the driver select a gear. See Automatic Transmission Operation on page 2-27 for more information. Your vehicle has a tow/haul mode. The tow/haul mode adjusts the transmission shift pattern to reduce shift cycling, providing increased performance, vehicle control, and transmission cooling while towing or hauling heavy loads. Press the button located on the end of the shift lever to turn the tow/haul on or off. While the tow/haul is on, a light on the instrument panel cluster comes on. 2-31