JD 9400 combine hyd overheating

chuckinnc · Nov 3, 2020

Time to get the beans up but the combine shuts down with hydraulic overheating, Just put in a hydraulic radiator/cooler, old one had a bad leak, now it shuts down after a few acres. The lines going into cooler don't feel hot but the hyd tank is very very hot, hydraulics work so pump must be working ok, reminds me of a car when the thermostat is stuck. Does anyone know if the 9400s had a thermostat in hydraulic line or maybe a bypass valve somewhere?

coonie minnie · Nov 3, 2020

I'm Asking a dumb question... you are putting the grain auger back into the neutral position, correct? If you leave the switch in "out" or "in" vs neutral, it can overheat the oil.

J Hamilton · Nov 3, 2020

You did make sure the caps or plugs were removed from the new cooler lines before installing? I know it's easy to overlook something like that.

chuckinnc · Nov 3, 2020

Yea the switch in the cab is in netural, I did have problem with the hyd cylinder controlling the auger running pully not fully retracting, ordered a new spring and put on, that didnt help, now I use a ratchet strap to make sure its fully retracted and auger isnt running.

andy r · Nov 3, 2020

A high pressure internal leak can cause the oil to heat up rapidly. A JD 9400 has a great deal more hydraulics than a JD 6620, but my JD 6620 had two internal high pressure leaks and it would cause the temperature monitor to come on after 10 minutes or so. One internal leak was on the main hydraulic valve used to manually lift the header/etc. and the second internal leak was on the secondary valve used to swing the unload auger/etc. Both leaks occurred where an "O" ring had failed on a fitting that screwed through one passage and into another on the valves.

jm. · Nov 3, 2020

I think you have answered your own question, when you say the lines to the cooler are not hot, has to get to the cooler something plumbed wrong or a flow problem.

showcrop · Nov 4, 2020

2X cool cooler lines. There must be an obstruction there.

matthies · Nov 4, 2020

Have you started the combine and felt the lines on the valve stack?? Maybe you can find one that warms up faster than the others.

JD 9400 combine hyd overheating

chuckinnc

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coonie minnie

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J Hamilton

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chuckinnc

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andy r

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jm.

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showcrop

Well-known Member

matthies

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