GMC Sierra
GMC Sierra

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Recommended Fuel
Use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, an audible knocking noise, commonly referred to as spark knock, might be heard when dri ...
Folding the Seatback
To fold the second row seatbacks:
1. Remove anything on or under the seat.
2. Place the armrest in the upright position, and unfasten the safety belt.
3. Pull forward on the reclining seatback stra ...
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 ...





