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. See “Automatic Engine Grade Braking” within Tow/Haul Mode on page 9‑26.

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 10‑18.

On a long uphill grade, shift down and reduce the vehicle speed to around 88 km/h (55 mph) to reduce the possibility of the engine and the transmission overheating.

    See also:

    Warranty
    OnStar equipment may be warranted as part of the new-vehicle limited warranty. The manufacturer of the vehicle furnishes detailed warranty information. ...

    Warning Lights, Gauges, and Indicators
    Warning lights and gauges can signal that something is wrong before it becomes serious enough to cause an expensive repair or replacement. Paying attention to the warning lights and gauges could preve ...

    Securing an Add-On Child Restraint in the Vehicle
    WARNING A child can be seriously injured or killed in a crash if the child restraint is not properly secured in the vehicle. Secure the child restraint properly in the vehicle using the vehicle safet ...