Dogde 4x4 with 5.9 and automatic.I first noticed a vibrating or a wierd noise that was on and off while driving, but would stop if I accelerated or let oo the gas pedal. Now when ipit it in reverse it goes but shutters. It is also doing it in drive when I come to a stop sometimes it feels like someone rear ended me and the truck dies. It will restart easily but will shutter ubntil I take off . Shifts fine otherwise what is wrong?