Oh man guys....

I want to take a shotgun to the GC right now.

So....

I took it to a reputable axle shop. The owner said things didn't look all that bad when he popped the diff cover. He did say it wouldn't hurt to rebuild the front diff but he didn't think it was the source of the roaring/whirring sound. So we both decided to go ahead and do the work. He gets done, sound still there . He recommended I replace the TC

So, I finally got a chance to get out there and I removed the front drive shaft and took her for a whirl. And the sound is there!

So based on this, can I safely say that the problem is not at the transfer case? I'm pretty sure I can right? And.. it almost has to be in the diff. Anything else I should check? Would a sticking caliper cause this sound?

 

Your mechanic had to remove the calipers to do the diff rebuild. He should have noticed a dragging caliper. About the only thing left is the t-case.