for a while now ( few months ) at about 30mph my car will pick up a vibration thats felt throughout the car pretty much. it goes away above that though but will be felt again slightly at about 50 mph. then it will go away again. when i shift into gear from park ill get a thunk sometimes too. the car also will 'clunk' when im cruising along and let off the gas. it will 'clunk' again when i get back on it as well. it does not do it in park or neutral. just in gear. now.. im thinking tranny mount... maybe u joint... i thought maybe motor mount too, but it wont do it when its not in gear. thoughts? suggestions? ridicule?