Strange rubbing noise! Please help? Suggestions?

Got a question for you guys.
We were driving tonight and I started to hear a rubbing sound in the rear end. We pulled over and it smelt like burning rubber coming from the rear passenger side tire. But there is no wear on the tire and it wasn't touching or warm anywhere. It seems to be happening around 53-54 mph constantly. It did hesitate coming out of 4-H shortly before so could something be sticking maybe? Has it happened to anyone before?

 

Possibly the brakes. No rubbing or wear on the tire. Not entirely sure it would smell like burnt rubber but if your axle bearing is shot and diff fluid has reached it there could be a burning smell. Maybe someone else has a better idea.

 

Maybe the carrier bearing on the drive shaft...

 

That's more of what I was thinking but I didn't know how to tell if it was.