I have 84 trans am with a t5 and when I get at about 65mph it makes this howling like noise that only gets worse when I put the car into nuetral. not sure if its the tranny or rear end. the only thing I've figured out is its not tied with my rpms because i can take the car to 5 grand in 2nd gear and its not there but the moment i get above 65mph in 4th 5th or 3rd gear its there. Any ideas would be much appreciated.