I get a low grumbling noise when turning sharply at a very low speed. Backing out of the driveway, for instance. Sounds like the diff is working overtime...it's definitely coming from the undercarriage, but other than that I'm at a loss. Any ideas?

It's the V8 model so it's full time AWD, not sure if that makes any difference.

Drivetrain is still under warranty so I'm taking it to the dealer again tomorrow...but I'd prefer to have some ideas from the crew here before they tell me that it's "normal"...again.

 

Mine does it...

 

If it were me, I would immediately replace the diff and transfercase fluids. Inspect the magnetic drain bolts for excessive amounts of shards. How many miles? When or have you replaced the fluids yet? If so what fluid and what interval? I changed all of mine out at about 15K miles with the Amsoil series 2000 HD 75-90 gear oil about 4 years ago. 85K miles later I'm using the same fluid and no noises (smooth as silk). I'm going to change it out again when I change my spark plugs at 110K miles.