See also:

Electronic Range Select (ERS) Mode
ERS or manual mode allows for the selection of the range of gear positions. Use this mode when driving down hill or towing a trailer to limit the top gear and vehicle speed. To use this feature: ...

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. ...

Backing Up
Hold the bottom of the steering wheel with one hand. To move the trailer to the left, move that hand to the left. To move the trailer to the right, move your hand to the right. Always back up slow ...