I have a 2004 FX4 Off Road F150. Yesterday I was on the interstate and I heard a clicking noise coming from the back, kind of sounded like something was falling out from underneath the truck. I didn't run over anything and nothing was behind me so I kept going. Later on in the trip my back left tire felt like it was grinding on something, not consistently but in a certain spot every time the wheel turned. The grinding was real loud and was I could feel it in the drivers seat. I let the truck sit for a day and the same thing happened again. Any help?