'07 Tahoe Driveline squeek

[btfarm]

Wife's '07 Tahoe 5.3 has a squeek that she's been concerned about. Happens when accellerating from a stop. Pretty loud too but only in forward. I jacked it up, put it in neutral and slid underneath figuring it was certainly a u-joint. Manually turned the shaft and got a pretty significant squeek, squeek, squeek sequence in forward but not in reverse. Damned if it doesn't sound like it's inside the NP246 transfer case. No obvious play in the u-joints. I didn't pull the shaft because it's gonna go in for this. It's still got a month or so on the 5yr/100k. Bought May '06. TC is full and the rear diff is full of grape juice. 61k and change for miles.
Any guesses?

 

[ak diesel driver]

take it for a spin and then slide back under and feel the caps on the ujoints if you got a dry one it will be warmer than the rest and possibly HOT!