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:
Park Brake and P (Park) Mechanism Check
WARNING
When you are doing this check, the vehicle could begin to move.
You or others could be injured and property could be damaged.
Make sure there is room in front of the vehicle in case it begi ...
Running the Vehicle While Parked
It is better not to park with the engine running. But if you ever have to, here
are some things to know.
WARNING
Idling a vehicle in an enclosed area with poor ventilation is dangerous. Engine
e ...
Confident and agile driving experience
Two new engines are offered on all GMC Terrain models, each with fuel-saving
direct injection and variable valve timing technology. Vehicle highlights
include:
New 3.0L DOHC direct injected V-6 ...





