2004 Ram 2500 Hemi 42,159 miles. Detroit Locker LSD. It started with me backing out of my driveway. It felt like the rear diff was engaged. Then it POPPED. nothing else happened after that until a couple days later. While driving I heard a grinding noise sounded like it came from the rear. Now while driving I can hear a low grinding and I get pulled to the ditch. I feel absolutely nothing in the steering wheel. I have had the truck to a dealer for the rear diff. Everything is good. The U joints just got replaced it still does it. I can hear something which sounds like it is in the vicinity of the tail end of the tranny. Any thoughts on what this might be

 

Brakes? Parking shoes?