NHTSA Complaint #11687398 — 2012 GMC TERRAIN

GMC Consumer Relations Subject: Structural Undercarriage Safety Defect – 2012 GMC Terrain SLE Vehicle Information: Year/Make/Model: 2012 GMC Terrain SLE VIN: [XXX] Mileage at Purchase: 148,305 Date of Purchase: [XXX] Location: Rochester, New York I am filing a complaint regarding a severe undercarriage safety defect in my 2012 GMC Terrain SLE. The rear undercarriage of this vehicle shows heavy structural corrosion on suspension brackets and mounts. The condition produces clanging noises during normal driving, and an independent licensed mechanic has refused to work on the vehicle because the suspension integrity is unsafe. When I returned the vehicle to the dealer, I observed additional brackets being attached under the rear subframe area, suggesting reinforcement of compromised structural points. This confirms that the corrosion directly affects suspension geometry, alignment, and stability. This corrosion is not cosmetic. It is advanced structural deterioration affecting the mounting points for trailing arms and lateral links. These components are critical to safe turning, stability, and control. The corrosion compromises the ability of the suspension to keep the wheels aligned, creating serious risks of loss of control or wheel separation. What makes this more alarming is that the vehicle passed a New York State safety inspection on 07/13/2025, yet within days a mechanic refused to perform unrelated service because of the undercarriage condition. This raises questions not only about inspection validity, but also about the underlying durability and corrosion. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)