Grinding noise rear of truck

[Cool guy Mike]

I have a 2021 1500 Limited, when accelerating from standing start and turning either direction I will hear a grinding noise for about 3 seconds. The sound is a direct metal to metal contact. Straight line acceleration from a standing start has no noise. I have jacked up the truck, removed rear wheels looking for rub or wear marks. As of now I have not been able to find any. Brake pads are fine, truck has 44,000 miles, rotors have no grooved marks, unbolted the driveshaft checked rear u joint it is fine. Rear gear oil is fine. I would think this would be easy to find. Stumped........ Anyone have the same problem ???? Thoughts??? Truck tows quite a bit fishing boat (3000 pounds) camper (6000 pounds). On the boat ramp the rear axle is just touching the water ( not over ) for launching the boat. Thanks Mike