GMC Sierra
GMC Sierra

See also:
Special Application Services
○ Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000
km/ 3,000 mi.
○ Have underbody flushing service performed once a year. ...
Towing with a Stability Control System
When towing, the sound of the stability control system might be heard. The system
is reacting to the vehicle movement caused by the trailer, which mainly occurs during
cornering. This is normal wh ...
Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance.
However, if a customer wishes to write or e-mail GMC, the letter should be addressed to:
United States
GMC Customer Assistance ...





