if you take off from dead still floor it and in the first three car lengths it knocks ,rumbles, sounds like some one is under the car with a mallet banging on the floor it is the drive shaft, middle bearing,, Needswings has them at the best price for a good one ,( you don't want one made by ????? so order it from needswings and get the genuine bearing. if you take it to a shop to be checked ,,it can not be checked with the wheels hanging,, you need a drive on lift then go to the middle of the drive shave and shake it ,,push up pull down, push sideways do everything to make the bearing move, also look it see if the rubber on the outside of the bearing is not ripped, if it is ,,you found your problem.