A roaring sound is coming from the rearend

Hello, what is your question here? If you're told it's internal to the differential, then it may in fact be there. If you don't agree, obtain a second opinion for a hands on inspection. Nothing can be advised here other than to have this checked out and then act accordingly. Noises from the rear could be tires, wheel bearing, or internal differential noise. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops