Front Drive Shaft/FlexDisc Removed. Next Step?

[SeanIngstrum]

Okay, after going through all 7 gates of Hell and finding the 8th, the front drive shaft/shaft plate and flex disc are removed. No damage visible to the transfer case or shaft itself. The problem seems to be at the flange where the flex disc bolts to the differential. The flange is very loose. There is tons of play. It is obviously not connected to anything inside. I can spin it, push it up and down and side to side and all directions in between. I would of taken a picture but there is nothing really to see. I did see a nut in the middle of the flange so I took it off hoping I could pull that gear out of the diff (I really don't know what I'm doing at this point in my journey) but it just wouldn't come out. Pic of the nut included. I'm guessing it's held in internally? Anyways.....Worst news, I need a new front diff? I know you can buy new bearing kits for these diffs but do they need to be pressed? Are they magnetically fitted? I know that I will need to determine if mine is cast iron or steel, which I think mine is iron. Thanks for any help! I know I'll need it!!