[BlueHedgehog]

I've been searching and trying to figure out, what exactly can cause grinding/whistling (from now on grinding) sound, that happens periodically and on low speed (20-50kmh).
There are many posts talking about grinding sound, but almost none of them have video or sound reference in them.

I've captured this on video, perhaps someone recognizes this immediately.
https://youtu.be/4cnX5ry8NVE

In video:
00:27 switching gears up/down (no sound change)
01:08 switching off saloon ventilator (no sound change)
01:20 phone near rear ventilators/drive drain (grinding is really clear)
01:40 accelerating over 60kmh (sound goes away)

This happens sometimes, when driving constant speed or decelerating slowly.
I've noticed, that it's more frequent, when it is moist outside. And wasn't apparent, when it was try or snowy.

After slowing under 20kmh, sound goes away and is dead silent. When accelerating after that, no sound at any point.
After accelerating over 50-60kmh, sound goes away and doesn't mostly come back after slowing down.


What I have tried and have not affected the sound.
Apply hand break
Apply regular breaks
Wiggle side to side.

I have changed break pads and calipers, replaced differential simmerings (oil change).
Differential was replaced last summer (less than 1 year in my ownership) as a used part. I first noticed this issue few months ago.

This infrequenty of this happening is making me go insane