Something on the lines of the picture here. U-joint connection with a spline center that the pinion would go into and a big nut that would hold them together.
And yes, the internals are all jacked up. Carrier, Ring and Pinion all have damage, which is why I'm swapping rear ends.
Excuse me if I woke up on the wrong side of bed this morning BUT...
Why after reading this thread did I just receive a huge confusion headache!! T-3 time.
Maybe it is because you did not provide any pics & tell the whole story right from the beginning & we've been wondering what components you actually need?
At least now I am happy to hear you are going ahead & swapping the rear end, due to it being blown up, by post #16.
The corporate 8.25 rear ends are pretty much all the same, except for either an open carrier or a clutch based locker called a Trac-Lok.
If you obtain a free build sheet it will describe the type of rear diff & Transfer case your jeep came with, as well as probably the stock gearing of 3.73's off the top of my head.
Tom's the expert & can help out with spline info any pretty much everything else.
Are you intending on getting another rear end from the Junk Yard or?