I have a 7.5 everything is stock. I had new u-joints put in by NAPA. I then noticed a slight vibration at about 55. The rear U-joint had no way to center itself. So I thought it might be off center a little. I centered it within .005 side to side still had the vibration. Then the driveshaft come out of the car at 60. Very minor damage thankfully. I am wondering if NAPA put the wrong u-joint in the rear. Should it center when you tighten it down I thought the old one did ? The one that was in it you could set it anywere and tighten it up. So I also need a driveshaft if anyone is close to Dayton, Oh Thanks