After realizing I had an issue with my yoke in measuring for my d/s, I just need some clarification. So I've got a truck TH400 and when you slide the yoke in there's a solid thunk. I decided I don't have the o ring but the shoulder. Looks like I need to take out 2 1/2" of the splines on the yoke. How much do I over bore it? Are you all gonna make me take off the tailshaft housing to measure/mic the shoulder?