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Greenwich, NY | Ok, I guess no one had any information on the JD 3975 forage chopper. As a bit of general information we were trying to use the John Deere 3975 chopper with a 7120 IH Magnum tractor and the hydraulic were not compatible between the too, the JD chopper uses hydraulics controlled by electrical switches to control the chopper functions, chute rotation, defector angle, header height, header drive forward/reverse, and the pull tongue in or out.
For general information and to maybe help out someone else, this is what it took to make this combination work.
The JD 3975 forage harvester does not have a valve block that can be used with anything but the older JD closed center system,
open center or pressure compensated closed center with not work well with this system.
I did find out that JD had an "unloader" valve which could be added to the chopper "only" $600 for the part, I could not find any install or technical service bulletin about it or how to install it.
What we ended up doing was to install a hydraulic diverter valve back next to the JD hydraulic valve block. We did find a wire in the JD control box that was switched on with each and every switch activation in the control box. This wire went out in the multi-conductor cable leaving the control box and heading to the hydraulic control valve and all the sensors on the chopper. Of course that wire a blue one did not extend to the main body of the chopper or even near the hydraulic valve. It ends at the front of the chopper tongue under the fist removable cover and had a label on of diode 2 with a 3 pin connector. We used a trailer 4 pin connector to connect to the JD plug and ran that wire right in the JD wireway to the hydraulic control block and terminated that wire to the diverter valve and grounded the diverter valve to the existing ground on the hydraulic block. The plumbing was actually quite simple, I moved the two line from the tractor going to the JD hydraulic block over to the in ports for the diverter valve. The normally open ports of the diverter had a simple loop of hydraulic hose joining them and the two normally closed ports on the diverter valve went to the JD hydraulic block were the tractor lines had gone. The tractor flow valve is set for almost the minimum flow possible. In normal operation the tractors remote is detented to operate at this time the tractors hydraulic flow is leaving the tractor flowing to the diverter valve looping through the diverter valve and returning to the tractor. No over loading or excessive noise or heat being generated by the tractors hydraulic system. Whenever any function is selected on the JD controller the diverter valve activates at the same time as the JD electrically operated hydraulic valve does and the function works as desired. We have now used this for several hours in a day with no adverse noise or hydraulic issues to our tractor. | |
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John Deere 3975 forage chopper
