John Deere 4440 Quad Range pressure line pulsing

Rossco5983 · Jan 8, 2023

Got a 4440 quad range tractor I just replace the pump on due to a leak. Put a new pump for ASAP on it. Not for sure if the problem was there before hand but customer now has an issue on with the pressure line pulsing, can also feel it getting hot. The pressure and return lines have been Teed off for remote valve for loader, one line comes off of the SCV and the other line is teed off on right side of tractor. Don't think the issue was going on before pump was changed. The line going to the SCV is pulsing pretty consistently and getting hot. Just curious as to what I should check before I condemn the new pump or how to confirm the new pump isn't bad? You can pretty much feel the pulsing thoughout the whole system. I changed the fluid and filters, but didn't check the T/M pump screen when oil was out. Do I have a supply oil issue? Just kind of weird that this problem came about after replacing pump.

wore out · Jan 8, 2023

The loader valve should be ''closed center'' (to match the tractor hydraulics) and there should be NO flow in the lines to or from the loader valve unless a loader function is being used.

No flow would mean NO pulsing and no heating.

Did you check the standby pressure of the old pump, and then the new pump?

What MAY be happening is that the old pump was putting out less pressure than the new one does and now an (unneeded) pressure relief valve in the loader valve is opening, causing the pulsing of the line to it and the heating.

Cap off the lines to and from the loader valve, note if the problem goes away, and check the standby pressure of the new pump.

If the problem goes away with the loader valve out of the system and pump pressure is not unreasonable you will have to figure out what loader valve you have and if the relief pressure can be set up, or if something is wrong with the valve.

(Since this was apparently working previously I am ASSUMING the loader valve a the correct ''closed center'' unit.)

P.S., you should have checked the sump screen, what's on the screen and what a magnet pulls out of the area beneath it can provide clues as to what's happening with the transmission and final drives, brakes, and hydraulic system.)

used red MN · Jan 10, 2023

It sounds like you are not really a Deere guy. On
another note do your yourself a favor and make sure
the clamps that hold those lines in place are tight.
They tend to come come loose and the vibration will
wear a hole in them. Maybe a thermal gun could help
you find where the fluid is moving under pressure
causing the heating. I think wore out may have thought
up a pretty good possibility of what may be the cause.

John Deere 4440 Quad Range pressure line pulsing

Rossco5983

New User

wore out

Well-known Member

used red MN

Well-known Member

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