4440 Lost Hydraulics

[Shaggy97]

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?

 

[WTW]

What fitting are you referring to?? Where is it located on tractor?

 

[Shaggy97]

What fitting are you referring to?? Where is it located on tractor?

I miss worded it’s the pressure control valve sorry. It’s just below the rock shaft on the right side of the tractor.

 

[Tx Jim]

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

 

[Shaggy97]

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.

 

[Shaggy97]

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