Posted 6/30/2020 18:09 (#8345916 - in reply to #8344824) Subject: RE: Hydraulic issues in a JD 4430
What was the source of the new pump? Haven’t had much luck out of aftermarket reman pumps here.
I agree with pressure and flow check of front pump to diagnose the problem. It sounds like you have a low flow but adequate pressure so the priority valve is closing and restricting flow to rockshaft and SCVs so steering and brakes have enough flow to work still.
You don’t mention transmission problems or hydraulics chattering so I doubt there is a problem with your transmission/charge pump or the strainer.
How hot is the hydraulic filter getting? Can you keep your hand on it? If anything is leaking high pressure flow back to transmission sump, the amount of oil flowing through the oil cooler up front will be diminished and oil may get hot and thin making things worse.