Mine is noisy as hell in 4x4. I was told that gear-to-gear t-cases are always noisy but, I'm fairly certain ours are chain driven. Is this correct?

I'm also wondering if anyone runs gear oil in theirs as opposed to A/T fluid and if so, is it quieter or is doing that a REALLY bad idea?

Tc has pump in it don't think gear oil would be a good idea to thick .

Chain driven. It takes Dex/Merc III

Let me clarify a bit........the sound is along the lines of that constant droning sound that mud tires make on pavement.

Does it have fluid in it?

You sure its tcase and not ujoints?

Yes. I changed out all of the fluids right after I bought it and except for the front and rear diff's, everything looked as if it had been serviced regularly.

I have considered that. I'm not sure how to check them though. They feel tight and secure with no excessive movement. They're cheap enough, I suppose I could just install new ones and see if the sound goes away.

Last time they were greased? Shoot some grease in them and see if there's a change.

It can be hard to tell with the shaft in the truck.

Pull the shaft and check each joint.

does it sound like this video? this is mine and its trashed

No, mine is more of a low pitched whine or hum.

Bearings somewhere.

Do you HAVE mud tires on it?

^^Hahaha, this guy!!!^^