Vehicle Shudder problems of the 2011 Chevrolet Avalanche

Purchased a used 2011 chevy Avalanche with 87,000 miles one owner from a small dealership. After having the vehicle for about a week noticed it shuddering when pulling any kind of grade. Thinking it was some kind of misfire had all the plugs changed only to find that it also had an oil file problem with 1 of the cylinders. When the vehicle would shudder it was around 1500-2000 rpms. If I would give it more gas it made it past the 2,000 rpms and would shift with no problems. Needless to say the transmission is now toast as it gave out completely and needs replaced. No warning lights of any kind made me aware of a potentially serious problem. After reading more I am seeing that the transmission is something that gm has not fully taken care of as stated with older models. The transmission failed while driving on a major interstate roadway while nearing the top of a hill. It just went completely into neutral and would just rev the engine. The truck was carrying 3 adults and 2 children in car seats when this occurred. Thankfully we were able to get to the shoulder of the road safely. Currently the truck has 89,995 miles on it. I only put approximately 2000 miles on it since purchase.