GH 616 hydro howl

I recently purchased a GH 616. Low engine time, clean, new blades. So, the right side hydro can go forward just a bit quicker than the left, and hydros make a slight howl; fluid levels check per owners manual = ok. If I change hydro fluid & filter, will this help? Is there an adjustment for left/right "speed"?

Thanks much.

GH 616 hydro howl