Hello - novice driver here with very little mechanical experience.

My 1987 740 Turbo gives a metallic grinding noise when I'm coasting in any gear. If I apply a small amount of gas while coasting, the sound disappears, only to come back immediately when I let off the gas. Noise also disappears when I push in the clutch. However, I also get the same noise revving in neutral without the vehicle being in motion. I've recorded the neutral rev and have attached an mp3. Any input would be appreciated.

Thank you!

 

if its doing it in neutral, its the transmission or the clutch.