When I start from a stop there is a loud niose coming from the rear end that is like a cracking niose. This has been going on for a long time but now it is really bad. I had a friend try to see where the niose weas coming from only to have him tell me that the pinion on the rear is moving up about 2 inches and then coming back down. What is causing this to happen? I would bet that it is because I didn't put the pinion yoke on right and screwed something up. Any input would be appreciated. The rear is a 10b with a gov lock.