haveing vibration at 45mph and up only when i go over bump,expansion joint or just a really rough road,vibration will last for ten miles or 20 feet or till i hit next bump. Had trans rebuilt around memorial day ''08''problem seemed to start shortly after that during this time both front axle wheel bearings replaced,both front and rear u-joints and center bearing replaced,u-joints on front axle,track bar, steering dampner,front shocks,checked bolts on flywheel to torque converter they all were tight ,steering wheel stays pretty steady during vibration,any body have any ideas. Thanks Alot