Transfer case noise

Ok so i had a noise comming from my transfer case whenever I give it "power" I can avoid the nois by driving very gentil but if i need a lil power such as driving up on ramps the transfer case makes a noise. Ive read alot about it and am pretty sure the drive chain has stretched does anyone know a way i can test 100% and does anyone know Where i can find out how to replace the chain as Im pretty handy and my friend is a liscensed mechanic???
Thanks

There are a lot of companies that sell kits on-line. Can you give us some details about the setup?

Im not sure what you mean by the set up?? i have a np249 case if that helps

Yep that helps :)

I would (and have) swap that out for a 242. Its a better case and will fit right up in there if you get it configured for your output shaft. I got mine from Transfercases Unlimited and he is great to deal with and will ship you a properly configured 242 with a warranty for just a bit more than what it would cost you to put a chain and viscous in that 249 (if you need the viscous).

Ok so i had a noise comming from my transfer case whenever I give it "power" I can avoid the nois by driving very gentil but if i need a lil power such as driving up on ramps the transfer case makes a noise. Ive read alot about it and am pretty sure the drive chain has stretched does anyone know a way i can test 100% and does anyone know Where i can find out how to replace the chain as Im pretty handy and my friend is a liscensed mechanic???
Thanks

Same scenario I had on my 87 Cherokee. The chain is stretched and is rubbing internally on the casing. By now your case is damaged and your internal pump filter is clogged with junk, causing more wear due to lack of lube.

I got an NP242 case from a wrecking yard that only had 65K miles on it for $130. I swapped out the units and it worked fine.