well i couldnt really tell...it sounded like it was the spare tire squeaking at first...then when i wiggled my exhaust it made the noise...it also made it when i moved the suspension on the car (like if i pushed down or rocked the car)...but yeah verry agravating. if i went over a bump it would also happen...just leme know if you want me to find out exactly where it was hitting and i will look for you