Transfer case adapter gasket replacement instructions needed

As far as that last picture there is larger o-ring on the transmission side of the extension housing and If I’m understanding correctly a smaller o ring around that shaft. Originally, I thought that transmission fluid wasn’t supposed to be getting past the shaft in your last picture, but I noticed a tiny port under that shaft. I think that port allows the extension housing to fill with transmission fluid and the seal on the transfer case input shaft keeps transmission fluid from entering the transfer case, correct?

Hey Joe, I just wanted to say thanks for all your help. I got everything put back together and no leaks. Now I noticed that the rear drivers side u bolts are about shot. One has corroded all the way through one side and the other isn’t far behind. What can you tell me about replacing the U bolts?

The ones securing the leaf spring.

The ones securing the leaf spring

It’s the piece you highlighted in the last picture.