I lifted it off of all four wheels put it in drive and Pressed the gas. The transfer case moves around but nothing tO serious. I guess it only does it under pressure. I have a feeling it may be the rear differential since I just put a front differential in. I'm going to drain the fluid and refill to see if it help as for the vibration I think it may be the mass flow air sensor or something in that field . But again no check engine.