well it would seem your on track, I pulled the shaft off the steering box that I'm replacing and it seems to have some play in the slip joint. If I collapse it, the slip joint tightens up, dang it.
I appreciate the thought though
If anyone wanted it the u joint I was referencing was found here:
https://www.cherokeeforum.com/f2/steering-u-joint-replace-235721/
I'm not sure where you were thinking it would be welded in, both joints seems to be a pressed fit from a glance.