Mine does it too. Sometimes it's barely noticeable, sometimes it shakes the entire truck. I personally don't think it's "normal" or something the truck "just does". I finally got the service manager at the dealership to feel what it was doing and he says, "if it was MY truck, I probably wouldn't even notice it"...yeah, ok...that's his way of saying "I don't wanna take the time to try and figure THIS one out". He said he would put it "in the system" and see if he could come up with anything and wouldn't ya know it...I haven't heard a single word in the 3 weeks since I had it in there. I also have the feeling of running over little bumps when coming to a stop every so often. Dealer rotated tires and did alignment...still does it.