Vehicle Shudder problems of the 2011 GMC Sierra 1500

The contact called on behalf of her customer who owns a 2011 GMC Sierra 1500. The contact stated that while driving, the vehicle jerked and shuddered while downshifting. The stability trac and traction control warning lights were illuminated. The vehicle was taken to fiore Toyota (1000 s logan blvd, hollidaysburg, PA 16648) to be diagnosed. The contact was informed that the throttle body sensor needed to be replaced. The vehicle was not repaired by the dealer. The vehicle was repaired by the contact. The manufacturer was made aware of the failure and provided a case number. The failure mileage was approximately 103,000.

I have been hearing noises from rear of truck , and kept looking for the problem, finally grabbed the bed and shook it from side to side and sounds like the tire is fixing to fall off, took it to hall GMC in tyler TX. On 9-03-2013 they greased the leaf springs ? and said they had fixed the problem,but when its parked on a hill there is to much weight on axle for it to move and they knew that , so when I got home in the garage it still has an inch or so travel from side to side making an awful noise, took it back on after 5 or 6 phone calls was told to come and get the truck on 9-23-2013 , that they all do that ,if anyone has a 2011 chevy or GMC rear drive vehicle shake it from side to side give it a really good shake and next time you go around a corner fixing to pass someone it will scare you knowing that the axle is that lose.