2011 Chevrolet Express 1500 Cargo Owner's Manual - Page 246

9-32 Driving and Operating Cruise Grade Braking (Six Speed Automatic Transmission) Cruise Grade Braking operates only while Cruise Control is engaged in Tow/Haul Mode. Cruise Grade Braking assists in maintaining desired vehicle speeds when driving on downhill grades in cruise control by automatically shifting to lower gears when the cruise set speed is exceeded. While in the Range Selection Mode, Cruise Grade Braking is not available. See Manual Mode on page 9‑30. 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 9‑30 for more information on the Range Selection Mode. Grade Braking assists in maintaining desired vehicle speeds when driving on downhill grades by automatically shifting to lower gears when the driver desires to slow the vehicle by applying the brake. This reduces wear on the braking system and increases control of the vehicle. Also see Trailer Towing on page 9‑48 for more information. Drive Systems All-Wheel Drive If the vehicle has this feature, engine power is sent to all four wheels when extra traction is needed. This is like four-wheel drive, but there is no separate lever or switch to engage or disengage the front axle. It is fully automatic, and adjusts itself as needed for road conditions.