Hey everybody, I have a small problem and am thinking it is the u-joint. Whenever I'm in first gear and rev the engine to redline and shift fast, once it reaches about 5500rpm I feel like a rumbling from the rear and when i shift into second it rumbles even more, but that is the only time it does it. Do you think this is the U-joint ? It has to be something from the driveshaft. Thanks for the help