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Discussion Starter #1
Hi,

First time poster-

Just bought a new used JD 7510 with MFWD- Tractor has some issues as most do with this many hours and years (10K hours), but the main one I'm concerned with is that the MFWD won't disengage. I got underneath and checked the wiring and tested for power at the solenoid- I have good power and ground. I checked the ohms on the solenoid, and I have a little over 11 ohms. Don't know if that falls in the correct range or not. Next thing I think maybe should be to change the valve that the solenoid goes onto? Unless there's a way to test for leakage in the seals in the clutch box? I also got a nice surprise when I picked the front end off the ground and I have at least 1/2" of wobble in the front axle trunnion. So that's gonna have to come out too.

Would love it if someone has some insight on how to troubleshoot this MFWD unit before I go tearing it out of there! Thanks.
 

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You will want to check transmission and mfwd pressures. There is a test port right there close to the solenoid. The transmission system pressure has a test port on the bottom of the front transmission housing just above the mfwd driveshaft. compare the reading at the transmission test port and the mfwd test port. Pressure should be 245-265 psi at both ports. MFWD has pressure only when turned off. If you see more than 30 psi less in mfwd, there is excessive leakage and most likely seals in mfwd clutch and shaft are probably worn out. Sometimes even the housing is worn where metal sealing rings cut grooves in housing. The solenoid valve can be bad also but usually the valve being bad results in mfwd pressure being zero in my experience.
 

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Discussion Starter #3
You will want to check transmission and mfwd pressures. There is a test port right there close to the solenoid. The transmission system pressure has a test port on the bottom of the front transmission housing just above the mfwd driveshaft. compare the reading at the transmission test port and the mfwd test port. Pressure should be 245-265 psi at both ports. MFWD has pressure only when turned off. If you see more than 30 psi less in mfwd, there is excessive leakage and most likely seals in mfwd clutch and shaft are probably worn out. Sometimes even the housing is worn where metal sealing rings cut grooves in housing. The solenoid valve can be bad also but usually the valve being bad results in mfwd pressure being zero in my experience.
Thanks for the reply.

Today I removed the MFWD valve, cleaned it up and made sure the internal ports weren't plugged. Put it back on, still no disengagement. Tried a new solenoid for the heck of it, no change.

Plugged my pressure gauge into the port you mentioned, and I have 160 psi at 600 rpm, Gage comes immediately up and over 180 at 1000... Don't know past there because my gauge only goes to 180. it's pegged beyond 180 most likely well over 200.

Talking with the dealer I bought the tractor from, they tell me it takes 160 psi to disengage the clutch. I'm getting that and more, and still no disengagement. Sounds like it's time to drop the MFWD box.
 
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