Has a popping sound when I back up or put in drive. What is it? on 1997 Ford Explorer

Rearend is going out son-in-lae and his brother put all the tension on one side. Now it is popping when I back up and I can only do the speed limit which is 55. I did help on firguring out whatn it is.

Asked by for the 1997 Ford Explorer
You should have your rear difarenchel looked at
1 more answer
That's what happened to my car and the problem was the rear differential. Please go your mechanic as soon as possible needs to be lubricated it and set some oil on it. Don't wait or it will get worse.