JD 4410 Hyd. Pbelow problem

[tractorslinger]

I have a JD 4410 with 900 hours on it. I bought a 72 " finish mower a month or so again. I noticed when lifting the deck, there was a growl coming from the pump. It does it at 1600 rpm or below. If you lift it all the way to the highest point, the noise isn't very load, but when lifting to a desired height, its much loader. My loader is making the same noise, but only at 1400 rpm, not below or above at all.

I changed all fluids, filters, screens. No metal in suction line, but did see metal flakes in drain pan after changing fluid.

Loader/ 3 point operate as they should. No drop, no performance loss.

Any ideas?