Automatic Transmission problems of the 2011 GMC Sierra 1500

The contact owns a 2011 GMC Sierra 1500. The contact was driving up an incline approximately 5 mph and plowing snow in a residential driveway. When the contact shifted into reverse, the vehicle began to roll forward and the engine stalled. The vehicle came to a stop after the contact applied the brakes repeatedly. The contact stated that the failure would also occur when driving forward on an incline. The vehicle was taken to a dealer where the technician performed a road test and informed the contact that the vehicle was operating as designed. The vehicle was not repaired. The failure mileage was approximately 800.

The contact owns 2011 GMC Sierra 1500. The contact was driving 50 mph when the vehicle hesitated and was slow to accelerate. The vehicle was taken to the dealer and they advised that there were no failures and the vehicle was operating as designed. The vehicle was not repaired. The failure and current mileage was 1,500 updated 02/23/11 the consumer stated the vehicle would hesitate on acceleration. Whenever he attempted to accelerate, the engine would lag behind for a split second. When the engine did engage, the drive train would bang from the engine accelerating. The consumer also stated the vehicle would not hold in steady speed high gear. The transmission would continually go between 5th and 6th gear. When in 6th gear, the vehicle would lose speed. Updated 05/05/11.

On November 18, 2010, returning from vacation, driving a new 2011 GMC sierra sle pick up with less than 2,000 miles use, pulling a 24' travel trailer. The truck was in "tow" mode descending a 15% grade hill at approximately 45 mph. I was not accelerating when the truck down shifted itself automatically from 5th to 3rd gear and the engine accelerated to 4000 rpm. I applied brakes and truck shifted back to 5th gear. Fortunately conditions were dry and no accident occurred. Cruise control was not engaged at the time as terrain was very hilly and twisting. Truck shifted and accelerated without warning. Continued trip without further problems.