Ok reign. First off you CANNOT tell where the sound is coming from! PERIOD! So lets think about the things that are most likely the problem! LEAVE the tranny and transfer case out of it for the time being! Jack her up and check all 4 wheels and both driveshafts REAL GOOD! Them are usually the culprets in the noise you describe. It might be the throwout bearing.. Do all of these and make sure they are all in good health..
Then go to the tranny and transfer case. Drive it in 4 a while and then if it makes the noise shift the transfer case to NEUTRAL while it is making the noise. Then the same with the tranny...neutral while the noise is happening.
It is trial and trial again to find the noise.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />