2011 Chevrolet Avalanche Owner's Manual - Page 311

Driving and Operating Grade Braking is only active while the Tow/Haul Mode is selected and you are not in the Range Selection Mode. See "Tow/Haul Mode" listed previously and Manual Mode on page 9‑41 for more information on the Range Selection Mode. Grade Braking assists in maintaining desired vehicle speeds when driving on downhill grades by automatically implementing a shift schedule that utilizes the engine and transmission to slow the vehicle. This reduces wear on the braking system and increases control of the vehicle. Grade Braking monitors vehicle speed, acceleration, engine torque and brake pedal usage. Using this information, it detects when the truck is on a downhill grade and the driver desires to slow the vehicle by pressing the brake. 9-43 Cruise Grade Braking Cruise Grade Braking assists when driving on a downhill grade. It maintains vehicle speed by automatically implementing a shift schedule that uses the engine and the transmission to slow the vehicle. Cruise Grade Braking operates while Cruise Control is engaged in Tow/Haul Mode to assist in maintaining vehicle speed under loaded vehicle conditions. It utilizes vehicle acceleration and deviation from desired speed to determine the correct gear for the operating condition. If vehicle speed is above the desired speed the transmission will downshift to slow the vehicle. If vehicle speed is near or below desired speed the trans will upshift, allowing vehicle speed to increase. While in the Range Selection Mode, Cruise Grade Braking is not available. See "Range Selection Mode" under Manual Mode on page 9‑41. Drive Systems Four-Wheel Drive (Two Speed Automatic Transfer Case) If the vehicle has four-wheel drive, you can send the engine's driving power to all four wheels for extra traction. Read the following before using four-wheel drive. Notice: Driving on clean, dry pavement in Four-Wheel Drive High or Four-Wheel Drive Low for an extended period of time may cause premature wear on the vehicle's powertrain. Do not drive on clean, dry pavement in Four-Wheel Drive High or Four-Wheel Drive Low for extended periods of time. While driving on clean dry pavement and during tight turns, you may experience a vibration in the steering system.