3-Point Hitch Hydraulic pressure loss

[David V]

I have a 2013 LS 5055 low hours, runs great but i loose my setting on my back lift when I let off the throttle. I pull or trailer with hay and when traveling down tne road witn a steady throttle it holds steady where I set it. I let off the throttle and slow down and the lift drops....any clues? Front loader does not does this.
Thanks Dave

 

[robertsa]

Partially stuck open valve that can keep up at higher flow but not when rpms, and subsequently flow, drop?

Just a wild stab in the dark. I don't know as much as I should about tractor hydraulic system operation; I need to schedule time to study.