Traveling down the highway at 65 MPH the engine/transmission started bucking and you could hear the rear wheel lock up. The vehicle then would not shift and reduced the speed to 55MPH. Check engine light came on. Chevrolet is telling me the valve body needs to be replaced but keep driving it because it is on national backorder. After doing some research GM is hiding the issue and keeps installing faulty valve bodies. The GM fix is that they programmed the transmission to reduce speed when it notices excessive wear. GM is not standing behind the issue as it has been like pulling teeth to get a loaner vehicle.