I have a 68 Mustang coupe and have been hearing a screeching noise coming from the underside rear area of the stang and for the life of me canot figure out where it is comig from. It is very prominent when driving on the freeway at higher speeds. Has anyone else experienced this noise and what it is?? I have checked the wheels, brakes, and even changed out the speedometer cable, but no luck so far. Any suggestions??

This is a test.