2013 Chevrolet Tahoe Owner Manual - Page 291

Driving and Operating The vehicle has a shift stabilization feature that adjusts the transmission shifting to the current driving conditions in order to reduce rapid upshifts and downshifts. This shift stabilization feature is designed to determine, before making an upshift, if the engine is able to maintain vehicle speed by analyzing things such as vehicle speed, throttle position, and vehicle load. If the shift stabilization feature determines that a current vehicle speed cannot be maintained, the transmission does not upshift and instead holds the current gear. In some cases, this could appear to be a delayed shift, however the transmission is operating normally. The vehicle's transmission uses adaptive shift controls. Adaptive shift controls continually compares key shift parameters to pre-programmed ideal shifts stored in the transmissions computer. The transmission constantly makes adjustments to improve vehicle performance according to how the vehicle is being used, such as with a heavy load or when the temperature changes. During this adaptive shift control process, shifting might feel different as the transmission determines the best settings. When temperatures are very cold, 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 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 9‑32. 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 9-31 spin the tires. When stopping on a hill, use the brakes to hold the vehicle in place. Normal Mode Grade Braking Normal Mode Grade Braking is enabled when the vehicle is started, but is not enabled in Range Selection Mode. It assists in maintaining desired vehicle speeds when driving on downhill grades by using the engine and transmission to slow the vehicle. The first time the system engages for each ignition key cycle, a DIC message will be displayed. See Transmission Messages on page 5‑43. To disable or enable Normal Mode Grade Braking within the current ignition key cycle, press and hold the Tow/Haul button for three seconds. A DIC message displays. See Transmission Messages on page 5‑43. For other forms of grade braking, see Tow/Haul Mode on page 9‑33 and Cruise Control on page 9‑46.