Front Suspension Control Arm problems of the 2016 Chevrolet Colorado

Tl-the contact owns a 2016 Chevrolet Colorado. The contact stated that the vehicle gear unexpectely downshifts to 3rd as the vehicle approaches a down slop on a hill or road. The contact would have force the steering wheel has it violently shakes. No warning light illuminated. The vehicle was taken to an independent mechanic who changed the oil, informed the contact that the driver side upper control arm is faulty and needed to be replaced. The vehicle was not repaired. The failure recurred. The vehicle then was taken to a dealer poage Chevrolet 851 w pearce blvd, wentzville, mo 63385 where and appointment was set for next to have the vehicle diagnosed. The manufacturer was not made aware of the failure. The failure mileage was approximately 10,000. Ck.