what is making a roaring sound from the rear end? on 2004 Ford Explorer

There is a loud roaring sound from the rear end.When on the gas it is loud and off the gas alittle louder. It has 117,000 miles. Has alittle leakage from the rear differential. What could this be?

Asked by for the 2004 Ford Explorer
I HAD TO REPLACE MY REAR DIFFERENTIAL.
2 answers
Might be the wheel bearing. I had to get mine repaired and it was making a roaring noise from the rear.