Transfercase problem

97'/231j t-case/ 4.0L/auto

For a bit I was getting a "chirping" noise but couldn't figure it out till I had a friend and I get a closer sound/look and the noise is coming from the transfer case.
My question is this:
Can the chain be tightened? Or would I need a new one if its slack.
Is there anything on the inside that can break and fall off like a bearing, tab, etc...?
If there is something wrong with it, would it be easier to get another used one and swap or to fix?
I still have 2hi, 4hi, N, 2low so I think the gears are fine.

Loose chain is a rubbing sound...heard against the case. No fix but a new chain.

Have you checked the fluid level? Would be the first thing..before suspecting something else is wrong.

Also, chirping sound is a possible u-joint problem...don't overlook the driveshaft u-joints or cv-joints.

does any parts store carry the chain? and ya we looked everywhere, all the ball joints, u-joints, pullys, bearings, unit bearing/wheel bearing, driveshafts, the works. it wasn't till we noticed some slack in the transfer case more than usual and we jacked up the rear, threw it in neutral and started turning the rear driveshaft, the transfer case started making the same noise as we were hearing just slower and quieter. i just recently changed the oil in the transfer case and it was still fairly red and no shaving or particles that i could see.

Hopefully you can hear it, don't mind the thrumming sound from the tires.
http://youtu.be/DMZuK133RHA
First half is in drive and second half is in neutral, which led me to believe its the running gear and as I said before, we figured out it was the transfer case. Unless you guys and say different?
Another:
http://youtu.be/2RYXPtiJUTo

can anyone confirm if this is a stretched chain or maybe a bearing or oil pump inside the transfer case

Sure sounds like chain rubbing the case. Guess I wouldn't describe as a "chirp". Time to inspect the chain...and replace if necessary.

That's why I was hoping for someone to listen to it because I know I can sometimes describe things differently or others won't have the same description as I have. Looks like its time to swap a chain.