This is my first post. I have a 2000 f250 7.3 with the zf6 manual transmission. I'm getting a clunknown when goin from forward to reverse or reverse to forward. I have had the rear diff gone through and rebuilt. I also just spent 550 bucks having my drive shaft completely rebuilt. I'm still getting the clunk and it sounds like it's coming from the transfer case. What could it be? Everyone keeps telling me ithat is the slip yoke. And I'm positive that it is not.