Northcoast3800- Idid the same thing- I have a driveshaft shop about an hour away.
Ed, I so rarely have anyone to help me- but your method is the same one that I use when installing a transmission- it works great.
I began pulling the transmission apart and took some pics of the tail housing bushing. I also measured it. If my slip yoke protrudes 2.25” inside the housing, then is protrudes past the front edge of the bushing by at least 0.25”, so my fear has subsided- the yoke is probably fine, which means that the driveshaft length is fine. I may just end up installing 2 degree shims to get the pinion angle back to -0.5 degrees.
The most concerning thing i found today was the condition of the tail housing bushing- is is rough, I mean really beat up ….it looks like somebody had tried to remove it and gave up. Or did my -2.5 degree pinion angle/speed vibration cause this? Or was the vibration a result of the bushing being in such bad shape? Perhaps I will never know. To me, some of the wear marks look like they were caused by the slip yoke vibrating. See pics:
Tail housing bushing