4440 Lost Hydraulics

Shaggy97

New User
Trying to diagnose a hydraulic problem on my quad range 4440. I’ve lost steering, 3point lift, and both remotes. It all came shortly after I changed the pressure relief valve fitting that was leaking. Still have clutch and brakes. What should I start looking at first? Front pump, rear pump, relief valve?
 
Pressure control valve closes at 1700 psi so as to give power steering & brakes priority oil pressure. PCV can cause loss of scv & 3pt hitch when pressure falls below 1700 psi but it shouldn't affect steering. My guess is a piece of foreign material is in seating area of frt pump stroke control valve keeping SC valve from seating. Does your tractors hyd pump have a de-stroking screw? De-stroking screw is item 6 in link. https://partscatalog.deere.com/jdrc/sidebyside/equipment/74369/referrer/navigation/pgId/246896
 
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Pressure control valve closes at 1700 psi so as to give power steering & brakes priority oil pressure. PCV can cause loss of scv & 3pt hitch when pressure falls below 1700 psi but it shouldn't affect steering. My guess is a piece of foreign material is in seating area of frt pump stroke control valve keeping SC valve from seating. Does your tractors hyd pump have a de-stroking screw? De-stroking screw is item 6 in link. https://partscatalog.deere.com/jdrc/sidebyside/equipment/74369/referrer/navigation/pgId/246896
I’m not sure if it does or not I will check and see.
 
Upvote 0
Pressure control valve closes at 1700 psi so as to give power steering & brakes priority oil pressure. PCV can cause loss of scv & 3pt hitch when pressure falls below 1700 psi but it shouldn't affect steering. My guess is a piece of foreign material is in seating area of frt pump stroke control valve keeping SC valve from seating. Does your tractors hyd pump have a de-stroking screw? De-stroking screw is item 6 in link. https://partscatalog.deere.com/jdrc/sidebyside/equipment/74369/referrer/navigation/pgId/246896

So it doesn’t look like mine has the de-stroking screw
 

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