Knocking/Rattling/Noise when decelerating....DMF?

Hi guys, I have a '00 manual golf tdi, 460K. In august, when i got the car, i replaced the clutch, flywheel and pressure plate all together, PO said they were bad. got the LUK 17050 kit. Also replaced LCA bushings, rebuilt both cv's, replaced front pads.

Now 2 days ago, while decelerating (3rd gear), i heard a pretty audible knock, just once. when i applied the gas, it knocked again, and only once. slightly curious, i decelerated and accelerated a few times like that (just on/off the gas pedal) and it got worse. cut to coming off the highway, 5th gear deceleration (only on deceleration) sounded like a midget slamming a hammer back and forth. Same in 4th, and third. You can feel it through the whole car. if the clutch was engaged, the knocking goes away, and as you disengage the clutch, it begins again.

I noticed this knocking was very sparse, but still existent in 2nd, not heard in first.

took it home, looked underneath, didnt see anything standing out. jacked it up so wheels were off the ground, and cycled through the gears to see if i could replicate the issue. i could only hear it when disengaging the clutch in 5th gear (about halfway out). otherwise nothing. very audible from engine bay.

I am expecting what i really don't want it to be, which is the flywheel having failed already, but before tearing into the transmission i wanted to get some last minute thoughts and advice?

Did you replace the clutch fork (and most recommend the ball pivot)? I would assume that you replaced the throw-out bearing.

Does the clutch operation feel any different than when you'd done the install? That is, is the pedal feel and engagement location about the same?

Sometimes one gets a bad new part. I believe that there have been instances in which people have had early failures with SB Stage 2 clutches (a few bucks more than the Luk!): some spring clip letting go.

I REALLY hope that it's something else!

Are you sure it's not just the exhaust hitting something.....if the motor mounts, especially the dogbone, get sloppy it will allow too much engine movement resulting in knocking sounds especially when downshifting.

I'll second the dog bone, of the other mounts