2014 Chevrolet Silverado 3500 HD Crew Cab Owner Manual - Page 301

Driving and Operating vehicle is being used, such as with a heavy load or when temperature changes. During this adaptive shift control process, shifting might feel different as the transmission determines the best settings. When temperatures are very cold, the Allison Transmission and Hydra-Matic 6-Speed transmission's gear shifting could be delayed providing more stable shifts until the engine warms up. Shifts could be more noticeable with a cold transmission. This difference in shifting is normal. M (Manual Mode): This position is available on vehicles with the Allison Transmission or Hydra-Matic 6-Speed transmission. It lets drivers select the range of gears appropriate for current driving conditions. If the vehicle has this feature, see "Range Selection Mode" under Manual Mode on page 9-36. 3 (Third): This position is also used for normal driving. It reduces vehicle speed more than D (Drive) without using the brakes. You might choose 3 (Third) instead of D (Drive) when driving on hilly, winding roads, when towing a trailer, so there is less shifting between gears and when going down a steep hill. 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 control vehicle speed as you go down steep mountain roads, but then you would also want to use the brakes off and on. If you manually select 2 (Second) in an automatic transmission, the transmission will start in second gear. You can use this feature for reducing the speed of the rear wheels when you are trying to start the vehicle from a stop on slippery road surfaces. 9-35 1 (First): For the Hydra-Matic 4-Speed transmission 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 does not shift into first gear until the vehicle is going slowly enough. For an Allison Transmission or Hydra-Matic 6-Speed transmission, this position reduces vehicle speed without using the brakes. You can use it for major/severe downgrades and off-road driving where the vehicle would otherwise accelerate due to steepness of grade. When you shift to 1 (First) it provides the lowest gear appropriate to current road speed and continues to downshift as the vehicle slows, eventually downshifting to 1 (First) gear.