2005 Chevrolet Silverado 3500 Pickup Owner's Manual - Page 116

Tow/Haul Mode Tow/Haul is a feature on automatic transmission equipped vehicles that assists when pulling a heavy trailer or large or heavy load. Tow/Haul mode adjusts the transmission's shift pattern to reduce shift cycling, providing increased performance, vehicle control, and transmission cooling when towing or hauling heavy loads. If your vehicle is equipped with an Allison® transmission, you may have both Tow/Haul mode and overdrive disable. See "Tow/Haul Mode" under Towing a Trailer on page 4-69 for more information. Grade Braking (Allison Transmission® Only) Grade braking uses the engine and transmission to slow a loaded vehicle on hills in addition to using the brakes, saving on brake wear and increasing vehicle stability. The Allison Transmission®, when sensing the driver's desire to slow down while driving downhill, will automatically shift to the next lower gear range to assist in slowing down the vehicle. Grade braking is active and automatic both in Tow/Haul mode and normal shift mode. Grade braking is more aggressive when in Tow/Haul mode and can automatically downshift to SECOND (2), which is different than grade braking while in normal shift mode where automatic downshifts are limited to FOURTH (4). If your vehicle has an automatic transmission, it may be equipped with a Tow/Haul mode. The selector button is located on the end of the column shift lever. You can use this feature to assist when towing or hauling a heavy load. Turn Tow/Haul on and off by pressing the button until the Tow/Haul indicator light illuminates on the instrument panel. 2-30