NHTSA Complaint #11713202 — 2017 GMC SIERRA 1500

After 38,000 miles and 8 years of normal service (mix of city, highway, and 10% towing), my 8L90 transmission began to shudder occasionally. The problem first became apparent when driving slightly uphill, on cruise control at about 50 mph, or while slightly accelerating on a flat road, with no load in the box, and no trailer. It felt like I was driving across a rough patch of asphalt or rumble strips. Every half mile or so, it would shudder. Slowing down or speeding up stopped the rumble. The problem proved not to be caused by tires, U-joints, or AFM. The problem in fact was caused by defective GM transmission fluid, which was sold as "sealed for life", and rated for 200,000 miles, as factory-installed. That proved to be BS. If not repaired, this problem would lead to transmission lockup and/or lack of propulsion, which could contribute to a vehicle crash. The problem was solved by installing AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid, Product Code: ATLTP-CA. If GM properly cared for their customers, to make up for false advertising at the time of purchase, GM should publish and pay for GM Service Bulletin #20-NA-142, for all 8L90 owners, instructing owners to replace their transmission fluid every 5 years or 40,000 miles, whichever comes first.