Hello, hoping to get some in-put

I have a 93 grand cherokee with the 5.2 and a 249j. I have a grinding sound coming from the driveline when the transmission is in neutral and the transfer case is in neutral (not moving). it definitely sounds like a bearing.
A no brainer solution is the transfer case, but this is the 3rd one that I have put in and it still makes the same sound. this transfer case has 106k in it out of a 94. I was told there is a bearing in the transmission that could be the problem. any ideas? is this common?
Thanks

 

uh... just tossing ideas but id check to make sure the flywheel is tight to the converter... and if thats not it and it sounds like its coming from the tranny area... ride it out till the tranny blows and then stick another in it... make sure there both topped off on fluid also... of course...