I have noticed that when I'm decelerating in 4th, 3rd, 2nd, and 1st gear, there is a buzzing/whirling sound coming from under the gearbox (sounds like its coming from the tranny). The sound ONLY occurs when decelerating & right when I get under 2,000 rpms.

When the clutch is engaged, the sound stops.

What could this be?

Thanks in advance.

 

Does it do it while you're ACCELERATING as well? Mine is doing something similar, in the same RPM range, but I'm about 90% sure that my alternator is going out and the bearings in that are what's making my noise.

 

No, only when Im decelerating from what I can hear.