I own a 2011 silverado ls with a 4.8 and 4 speed auto. My problems are truck jerks forward on start up,when going from park to drive or park to reverse sounds like some one is striking the bottom of a metal pot with a hammer when its going into gear when at low speeds it bangs it gear. Took it to dealer they did nothing and told me it was normal. Really? We have 5 of the same truck at my job and none of them do any of it ,so they must be messed up i guess.anybody with same issues? I know the 6 speed has problems. I got handed a service bulletin #08-07-30-026a with says start vehicle with parking brake on! This is what i get for buying a silverado? Need some input really pissed off , thanks any help i would be grateful