[lespaul]

Stock 78 SC with 915.

This one sounds like someone put about 30 bbs in a coffee can and set it on the metal floor of the car. Someone not familiar with the car may not likely notice it. Almost a buzzing rattle.

It is not engine related, because it does not exist at any RPM when the clutch is disengaged or the car is in neutral. Thus, I conclude it must be drive train related.

It only exists when in gear and decelerating -- even when I just lightly let up on the gas or am barely maintaining speed. Most pronounced in 2nd at between 3000 and 3500 rpm. Can detect it in 3rd and 1st. Never tried in 5th. As the RPM's decrease the sound decreases. Drive train must be engaged and decelerating to hear the noise. Disappears on even the most gentle acceleration and engagement of drive train.

I would try to record it, but I doubt you could hear it with the other engine noise.

Ideas?