Boomer 40 Steering Valve

[PCABE5]

Any idea why a steering valve would be noisy, like a hydrostatic whine? Seems to whine more so above 2000 rpm and you only have to move the wheel a little either way and it will whine. No loader or other load on the front end and it does it stationary or moving.

Being that this valve is in the cab it's super annoying.