[rgunlock]

Going back through some of my old threads, I realized I'd never closed this one out. I was wrong about the noise coming from the transfer case. It was apparently transferring up the driveshaft from the rear end. I had just recently had that re-geared at a good drivetrain shop so it was "trusted" and I didn't specifically listen to it.

Turns out they either didn't use the right additive, or not enough of it. After filling with the correct gear oil and additive the noise disappeared.