jd 400 hydraulic problem

[keithcaldwell]

hi there i'm new to this forum

my jd 400 industrial tractor is having problems
i have had the loader control valve o/h, the priority valve o/h, the acumulator o/h and the pump o/h. i have changed fluid and filters. i recently did the flow test of the transmisson pump and the oil flowed out the oil cooler.
this is backwards.

any tips/help would be greatly apprecated
thanks

 

[mmurphy]

I am assuming o/h means over hauled?
For sure every thing is hooked to proper places?
And did this happen after o/h?
I have a manual somewhere, may take me a couple days before I can look at it.
If I remember correctly, it is much like the 301's if anyone has any info on them.
I am thinking there is a tube that should have some type of check valve going to that little tank. Did anything get changed there?

 

[mmurphy]

Kieth, I guess I am not sure which way from cooler or direction you are saying.
Your transmission pump is flowing first through the trans./hyd.filter, then to pressure reg valve. It maintains 150 psi if you have reverser, then drops pressure to about 60 psi to the main hyd pump. What is not used there should flow up to reservoir tank, and then drain down to cooler, then to brakes,and on to spraying gears in transmission.
The reservoir will also aid hyd pump when not enough oil from tranny pump or return flow from loader to main pump. The check valve in the top of the tank is for the bleed lines so it can vent in case pump requires drawing oil from there.