Yesterday noticed noise coming from front, please help mitigate the problem.

Yesterday noticed noise coming from front. I sounds like it has med to high pitch.
I may describe it like grinding/growling noise (may be it is not but having hard times to describe exactly), It sounds like gear on gear (but without metallic clings, muffled) or like tire with big and wide groves on pavement.
Don't see any drop in performance. And when I open windows it doesn't sound like noise from tires.
Noise is getting more high pitch as accelerating, but start to be noticeable only at 35 km/h and up. at 60km/h is loudest, then a bit quilter.
When I set Neutral and rolled car down hill with engine on - still same behavior.
Will try to run car downhill w/o engine running.

While on park did 0-4k rpms without that noise.

Haven't tried long driving backwards for long distance. On regular parking at malls and backing from drive way at 5-10 kmh no noise. But maybe I it has to be quite fast about 35-40 km/h to notice.

Oil level is fine a bit on lower side but within the level (it is 400km past needed change), didn't notice oil leaks. Don't know how to check tranny fluid level.

Any ideas? And if you have idea how to verify it?

Thank you.