On my 2008 rt I've recently had some bad vibrations but only under hard acceleration. Its hard to tell where it's coming from but it seems to shake the whole car. I'm thinking u joint or rear end vibration because the steering wheel hardly shakes at all. Everything looked ok when I put it on my buddies lift so Im not sure where to check. For you guys who have experience with the lx's any good place to start looking. I'm nervous about the chances that it's a transmission issue, although the car only has about 38k miles