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.

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 for more information.

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).

The tachometer for both the diesel and gasoline engine shows a dashed red zone and a solid red zone. The dashed red zone indicates where a transmission shift occurs for full engine power. When using grade braking, the transmission's shift point is adjusted to just prior to the solid red zone, providing the benefit of additional engine braking.

Grade braking driving within the dashed red zone is normal, both the diesel and gasoline engine have been designed for this grade braking feature. Do not allow the engine to go into the solid red zone. Apply the vehicle's brakes for a short time to slow down if you are driving on a long hill and the tachometer needle enters the solid red zone. See Towing a Trailer for more information.

If your vehicle has an Allison Transmission, you may have the overdrive disable feature. The overdrive disable feature prevents the transmission from shifting into FIFTH (5) gear. The selector button is located on the end of the column shift lever. You can turn overdrive disable on and off by pressing and holding the button at the end of the column shift lever until the indicator light, on the instrument panel, illuminates.

If your vehicle has both Tow/Haul and overdrive disable, tap the button once to enable or disable Tow/Haul, and press and hold the button to enable or disable overdrive disable.