Denny---I find that you have a great knowledge of things mechanical, and I put a high value on your insights. Please keep in mind that I play at hotrods for fun, but it has never been my career. Really, I'm not sure exactly whats going on with the yokes. I like the idea of pushing a weld rod up the tailstock to probe for a restriction, and I think there is good credibility to your theory of a twisted spline. If I do pull the driveshaft, I will try the other yoke and see how far it will go in. I cleaned the outside of the yoke thats on the driveshaft, but I never looked at the inside of it before I assembled it. Maybe its a twisted spline, maybe its packed full of rust and grunge. I certainly wouldn't want you to pull your post!!!!!!