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 have to be used so much that they would get hot and no longer work well.

The vehicle can tow in D (Drive). Use a lower gear if the transmission shifts too often.

When towing at high altitude on steep uphill grades, 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 transmission in P (Park) for a few minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating on page 10‑20.

    See also:

    Engine Cooling When Trailer Towing
    The cooling system may temporarily overheat during severe operating conditions. See Engine Overheating on page 10‑20. ...

    Trailer Towing
    If the vehicle has a diesel engine, see the Duramax diesel supplement for more information. If the vehicle is a hybrid, see the hybrid supplement for more information. Do not tow a trailer during br ...

    Infants and Young Children
    Everyone in a vehicle needs protection! This includes infants and all other children. Neither the distance traveled nor the age and size of the traveler changes the need, for everyone, to use safety r ...