NHTSA Complaint #11479800 — 2017 GMC CANYON

After 5 years and 2 months of ownership of this vehicle, at ~52,000 miles it began to develop a shudder in the driveline, that I originally ascribed to an imbalanced rear wheel. After checking the rear wheels for balance, that cause was ruled out. I took the vehicle back to the GMC dealer where I had purchased it new. They claimed that the cause of the problem was a defective transmission fluid that somehow became contaminated with water. They offered to flush the entire transmission and install new 100% synthetic transmission fluid for a cost of $770. When I complained about a vehicle with 52,000 miles developing transmission problems the dealer consulted with GMC, and then agreed to flush and replace the allegedly defective fluid without cost. Upon further investigation, it appears as though the origin of the issue is not due to the nature of the fluid, but rather the use of an undersized torque convertor in this 8-speed transmission, which began in the 2017 model year. The smaller size and inadequacy of this torque convertor design is the root cause of this shudder, which not only has presented itself in the 2017 GMC, but also in corresponding GMC/Chevrolet models using the same transmission. The danger of a transmission failure can have catastrophic safety consequences for the driver, passengers as well as the motoring public, not to mention a very large transmission replacement charge for the owner. There is currently a Class Action lawsuit in the State of California for this notorious "Chevy Shake."