I've noticed recently a fairly faint rubbing noise that appears to be left rear. Rub rub rub at maybe three times the speed of wheel rotation is my guess. Only noticeable on quiet tarmac around 30-40 mph. It seems worse when cold, and seems worse on right hand bends. I expect it'll be hard to find out what is causing it, but wonder if anyone on here has a clue. Rear diff was replaced a year or so ago, if that matters.