Help ID a noise

[Lumpy05]

1999 Boxster ~85,000 miles on original clutch.

I have a noise that only happens when the car is in gear with the clutch engaged. Does not change pitch with engine speed, it is more noticeable at low speeds but I think that just because its quieter. Sounds "swirly"?? Not shrill or low a medium tone that kind of swirls.

My thought is that its the clutch plate slipping indicating a need to change the clutch?? I don't notice any slippage in the clutch. I seem to have ruled out brakes/rotors, it doesnt change with speed or change with brake application. I seem to have also ruled out a engine related sound, it doesnt occur when the clutch is pushed in. I dont think its a wheel bearing as the sound doesnt change with speed.

Any thoughts or opinions?

[ALLSPEED]

Post a copy of the noise and someone might notice it.

[wvicary]

Does it stop if you have the oil fill cap removed?

[Lumpy05]

Does it stop if you have the oil fill cap removed?

I'll check on the oill fill cap. The AOS was replaced at ~ 72k miles.

I'll see if I can capture the sound on recording, its pretty subtle but definetly not normal.