My '87 Syncro is experiencing a noise emanating from the transmission area.
It does not sound like it's internal to the transmission, it's not a gear
whine sound. I would describe the sound as rotational vibration sound. I do
not feel the vibration, just hear it. The sound occurs only when I let off
the gas and coast, as when approaching a turn or going down a slight hill.
The sound will go away if I accelerate. It will also go away if I push in
the clutch pedal.

The transmission does have a driveshaft decoupler. The sound is unaffected
by whether the driveshaft is coupled or decoupled. It also made no
difference when I removed the driveshaft altogether.

Suggestions as to what might be causing this sound?  I'm guessing it could
be a throw out bearing or something else in the bell housing.

-Mark
Seattle WA
1987 Syncro Westfalia