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 ownership has changed, OnStar may send a voice message to the vehicle, requesting updated account information.
See also:
Footnotes — Maintenance Schedule Additional Required Services — Severe
a) Extreme service. For vehicles mainly driven off-road in four-wheel drive or used in farming, mining, forestry, Department of Natural Resources (DNR), or snow plowing.
b) Check all fuel and vapor l ...
Hitches
It is important to have the correct hitch equipment. Crosswinds, large trucks going by, and rough roads are a few reasons why the right hitch is needed.
• The rear bumper on the vehicle is not inte ...
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 ...