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:
OnStar Additional Information
Transferring Service
Push to request account transfer eligibility information. The Advisor can assist in canceling or removing account information. If OnStar receives information that vehicle owners ...
Safety Chains
Always attach chains between the vehicle and the trailer. Cross the safety chains under the tongue of the trailer to help prevent the tongue from contacting the road if it becomes separated from the h ...
Roadside Assistance Program
U.S.: 1-888-881-3302
TTY Users (U.S.): 1-888-889-2438
Canada: 1-800-268-6800
Mexico: 01-800-466-0801
As the owner of a new GMC, you are automatically enrolled in the Roadside Assistance program.
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