slip yoke problem / TF 727

I am having the same problem too, but kind of in reverse. I have a cast iron OD 833 out of a '75 Dart, and the yoke Brewer's sent me fits the same way 360duster described. But the funny thing is it fits my '68 A-body 833 beautiful with no problems. Both are 30 spline. I have to assume the early main shaft has a different spline angle than my later OD unit. I have the OD box completely torn down on my bench, and the yoke splines on the main shaft are perfect. No burs or dirt. WTF!!!