I have a problem that nobody can find. I hit some bumps or railroad tracks at 45mph or so and the Commander starts banging something in the middle bottom so hard that it shakes the whole Commander and sounds like something going to come through the floor. It sounds like a blown tire, but it's not. The only way stop it, is to throw the Commander in reverse drive back a little and then go forward and it stops. The dealer don't know what it is, since it won't happen while they had it and they checked everything out and it was fine. Anybody experience this?