Baystate Jeepers

Big thanks to Duncan and Dennis for sticking with me yesterday. As I pulled out of F&F the rear DS yoke end u-joint came loose, taking out part of the yoke in the process. Took the DS off, decided swapping in my spare rear DS wasn't worth it, and drove home in front wheel drive. Then discovered that the PS system was leaking (fluid hitting the exhaust manifold is a smoky sign) so we stopped to tighten that down. A little while later my jeep was still smoking, discovered that the extra stress on the front diff was heating it up more than usual, so the overflowing diff oil was getting everywhere and also hitting the exhaust manifold. Moved the front breather tube until it hung by the road so the overflow wouldn't get everywhere. Almost made it home when I heard angry sparrows, so I slowed down to ensure the front CV wouldn't overheat again and seize... and I made it.

Any suggestions for checking the u-joints in the future? I crawled underneath to check stuff Sat night and couldn't get the DS to budge by hand so I thought it was ok, but maybe it was "locked" in gear so I couldn't tell. Simply put the T-case in neutral next time?

I'd recommend tcase in 2HI and tranny in neutral.
That should decouple the F & R and allow both DS's to move freely.

I have a hard time inspecting the CV in the front drive shaft (or rear with SYE) without dropping that end out of the vehicle and actually inspecting it. The slip in the shaft is still tight enough to hold worn out parts in place.

I also find that when the center ball goes in a CV joint, there's only a 50/50 shot of being able to rebuild it once. If the tolerances are just a little out of whack, it won't last long. I find them difficult to assemble in my home garage, too.
A lot of light is needed, because visual inspection is also required. You're looking for any shiny deformities in the yokes and ears around the caps. Broken or missing seals around the caps. Side to side movement in the u-joint, and when you look for movement, if at all possible, you want to use a tool (prying action, but not hard enough to bend anything) to slide the u-joint through all phases of its cross. (4 caps, so you're looking for movement in all four directions.) If there's movement with your bare hands, it is really bad.

That's awesome, that people hung out and helped.