Swapping 1992 5 speed/transfer case into 72 ?

[RShaips]

I am building a 1972 1/2 ton 4x4 4 speed truck and may have the oportunity to get a 1992 1/2 ton 4WD truck from my brother in law real cheap. It has a 5 speed transmission that is making lots of noise when its in gear but quits when you push the clutch in. I'm thinking it might just need a new throwout bearing and clutch plate. Although it does have 300,000 miles on it! How hard are these to rebuild and how difficult of a swap is this ? My truck has the body off now and this is the time to make changes.Thanks for the help.