For a few days I have this "reving noise" come from what sounds like the tranny. When ever the car is in gear it makes a reving sound and the higher the rpms the louder the noise but when you change gears the noise goes away for a second. Also if I lightly accelerate the noise gets a lot louder. Tonight i was going like 65 down the highway and put in neutral and just coasted along and the noise went away as soon as I pressed the clutch to go into neutral. This a 99 a4 1.8 with manual tranny. Any ideas?

Thanks in advance.

 

Is the noise there when you put it in neutral and take your foot off the clutch?

 

No its not but it does come back and you can feel the vibrations if you hit the gas while in neutral.

 

Figured it out: it was the flex pipe on the exhaust it broke off the pipe to the front exhaust.