Driveline whirring/ticking sound on decel

[citizen_insane]

This is something that has recently started happening and I can't find a source for the sound. Here's a video (just for sound): https://www.youtube.com/watch?v=UiIkBADKhMk.

Here's what I know

• The issue is independent of engine speed, it is not just typical M20 ticking sounds
• Frequency is dependent on vehicle speed
• I did not make any changes to the car when the sound started happening (my setup has been the exact same for the last year)
• I can only hear it during decel, but it's possible it's just masked by the engine sound during accel
• It's not a zip tie wrapped around the driveshaft to prank me

I had the car up on my coworker's lift the other day and was unable to find anything hanging down that could hit the prop-shaft or axles. The center shaft bearing is new as of 4 years ago, I pretensioned it as per the manual. The wheel bearings were all replaced 2 years ago and don't feel loose. Anyone got an idea what it could be? I'm concerned it's internal to the diff or trans so I've been avoiding driving the car. It's possible something is damaged, the car has a turbo making 15psi and makes a lot of torque.

[tomstin]

If you push the clutch in, take the engine out of the equation, the sound is vehicle speed dependent and not engine speed. If so, then the noise is either transmission or drive line. And you suspect it is only on deacceleration. I would suspect universal joint. As I recall, one tends to load on acceleration and the other on deacceleration.

[citizen_insane]

If you push the clutch in, take the engine out of the equation, the sound is vehicle speed dependent and not engine speed. If so, then the noise is either transmission or drive line. And you suspect it is only on deacceleration. I would suspect universal joint. As I recall, one tends to load on acceleration and the other on deacceleration.

Correct, this is what I mean when I say the sound is independent of engine speed. With the clutch in, the sound is still dependent on vehicle speed. I think what I probably need to do is get the car running on jack stands and get under there with a camera and see if I can tell exactly where the noise is coming from. I was hoping someone had heard a very similar noise and knew exactly what it is, but it's really not that much work to get the car in the air.