2025 GMC SIERRA 3500 — TIRES:SIDEWALL
I am reporting a potential safety defect involving Goodyear Wrangler TrailRunner AT tires size LT275/65R20. I purchased a new 2025 GMC Sierra 3500HD in August 2025. By the time the vehicle reached approximately 1,800 miles, noticeable sidewall bulges appeared on both rear tires. As a 36-year automo...
2020 GMC SIERRA 3500 — POWER TRAIN
My truck has been exhibiting hard downshifting at certain speeds, when the powertrain loads up such as a grade change, and requires a downshift. I have complained about this issue to the dealership as early as 2022, and 33,185 miles. The dealership made me pay for a transmission $388.90 flush whic...
2025 GMC SIERRA 3500 — EXTERIOR LIGHTING
Randomly when the truck is turned on, the turn signals will stop working, no noise, nothing. When this happens, the infotainment system also stops working. It is unsafe to be driving and not knowing if your signals are working or not. This has been happening since the truck was purchased from the de...
2025 GMC SIERRA 3500 — UNKNOWN OR OTHER
Randomly when the truck is turned on, the turn signals will stop working, no noise, nothing. When this happens, the infotainment system also stops working. It is unsafe to be driving and not knowing if your signals are working or not. This has been happening since the truck was purchased from the de...
2025 GMC SIERRA 3500 — ELECTRICAL SYSTEM
Randomly when the truck is turned on, the turn signals will stop working, no noise, nothing. When this happens, the infotainment system also stops working. It is unsafe to be driving and not knowing if your signals are working or not. This has been happening since the truck was purchased from the de...
2024 GMC SIERRA 3500 — FUEL SYSTEM, DIESEL
The contact owns a 2024 GMC Sierra 3500HD. The contact stated that while driving at various speeds, there would be a diesel odor coming into the cabin of the vehicle. The failure had become more persistent, causing black smoke to enter the cabin of the vehicle. The failure caused the contact and oth...
2024 GMC SIERRA 3500 — ENGINE AND ENGINE COOLING
The contact owns a 2024 GMC Sierra 3500HD. The contact stated that while driving at various speeds, there would be a diesel odor coming into the cabin of the vehicle. The failure had become more persistent, causing black smoke to enter the cabin of the vehicle. The failure caused the contact and oth...
2023 GMC SIERRA 3500 — POWER TRAIN
August of 2025 [XXX] purchased a certified GMC Sierra 3500. The truck had been traded in May and sat in their service department waiting on a valve body. At this point, we knew this. [XXX] had done research on it, and felt confident in being told the valve body was completely replaced and now work...
2024 GMC SIERRA 3500 — POWER TRAIN
This 2024 GMC Sierra Heavy Duty has experienced a continuous pattern of major mechanical and electrical failures since early ownership. The vehicle required a complete engine replacement under warranty at approximately 43,626 miles. Since that time, the vehicle has continued to experience repeated i...
2024 GMC SIERRA 3500 — ENGINE
This 2024 GMC Sierra Heavy Duty has experienced a continuous pattern of major mechanical and electrical failures since early ownership. The vehicle required a complete engine replacement under warranty at approximately 43,626 miles. Since that time, the vehicle has continued to experience repeated i...