Driving on Grades
Reduce speed and shift to a lower gear before starting down a long or steep downgrade. If the transmission is not shifted down, the brakes might get hot and no longer work well.
Vehicles can tow in D (Drive). Shift the transmission to a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions.
The Tow/Haul Mode may be used if the transmission shifts too often.
See Tow/Haul Mode on page 9‑42.
When towing at high altitude on steep uphill grades, consider the following: Engine coolant will boil at a lower temperature than at normal altitudes. If the engine is turned off immediately after towing at high altitude on steep uphill grades, the vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked, preferably on level ground, with the automatic transmission in P (Park) for a few minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating on page 10‑23.
See also:
Service Publications Ordering Information
Service Manuals
Service Manuals have the diagnosis and repair information on the engines, transmission, axle, suspension, brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletin ...
Lower Anchor and Top Tether Anchor Locations
Rear Seat
(Top Tether Anchor): Seating positions
with top tether anchors.
(Lower Anchor): Seating positions
with two lower anchors.
The rear outboard seating positions have exposed metal anch ...
Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck
capability combined with greater off-road versatility. It is highlighted by a
bold exterior design, enhanced all-terrain ...





