I just did some testing in our cul-de-sac, and now I think the problem is related to the TOD transfer case...

I rolled down the windows and went round-and-round to the right to get the noise to occur. When it did, I got the impression that it wasn't really coming from the back, nor was it coming from the front either. Hmm... right in the middle, then, and there's only one mechanism there that likely could be doing something like this.

I straightened her out, shifted into 4-low, and went up and down the street. It was kinda noisy, and even made a couple of screechy sounds. So I brought it back down to the cul-de-sac and went around it... WOW! What a racket!! It was making all manner of clicking and slipping and grinding noises - NOT the usual gear whine from the transfer case.

So I am going to tell the service writer to check the t-case when I bring it back for the rest of my fixes (still waiting on one part) and see if they can find something wrong with it.

Good luck to me...