# Hydraulic system problems with a John Deere 6400



## AmosB (Jun 25, 2017)

The hydraulic lift on my John Deere 6400 was jumping up and down. Now it is working fine but I have lost power steering and power to my SCVs. When I pick up something heavy with three point hitch lift arms, the power steering starts working. But when I let it back down, the power steering goes out again. I am having trouble figuring out why. Anyone know anything about this? Any help will be greatly appreciated. Thank you.


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## pettibone (Jul 18, 2015)

It sounds like something in the priority inlet valve which controls where the oil pressure goes. There is a spool you can take out to check. The hydraulic system doesn't make any pressure until it senses a need which is controlled by the inlet priority valve. That's the valve in the middle where the pressure line from the pump hooks on.


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