John Deere 3720 PTO not working

pfeener · May 8, 2015

I recently purchased a 2009 John Deere 3720 with 600 hours on it. It has always had a FEL and a backhoe on it so I don't think the PTO was ever used. I tried the PTO but it does not engage. I have 12 volts to the PTO solenoid with the PTO switch engaged and the resistance through the PTO solenoid is around 10 ohms, which is what it should be. I removed the bottom allen screw on the PTO valve and I get plenty of flow through when I kick over the engine. I haven't measured the pressure to, or through, the valve yet, but I don't think that's the issue. My thought is that the PTO spool is stuck or gummed up from lack of use. Since a new PTO valve is around $800, I'd rather take a different route. Has anyone rebuilt or cleaned out one of these PTO valves and is so, what's involved. I'd love to be able to rebuilt it with new o rings and seals, but it looks like Deere doesn't offer parts for this valve.

arlen4720 · May 8, 2015

I would just tear it apart and clean it up. I haven't did that with a PTO valve, but I have disassembled many other valves. Like you said, the solenoid is probably just gummed up.

jenkinsph · May 10, 2015

Not familiar with this specific valve but if you remove the solenoid coil you may be able to free the spool without taking it apart. I would try that first. Your tractor isn't very old and I would be less inclined to think of it as gummed up, more likely just stiff. I would first try to rotate the spool, then pulling on it carefully.

DLTTrekkers · May 12, 2015

? Is there a 540 and a 1000 PTO speed ? Mybe in neutral ?

olllotj · May 12, 2015

If it has a Mid PTO it could be that shifter not fully engaged or engaged to the mid.

pfeener · May 12, 2015

The PTO valve spool was indeed stuck. Before I took anything apart, I figured I'd try a little different tactic. I energized the PTO valve and gently tapped on the valve and solenoid with a small hammer. I heard the spool click open and the PTO started turning. Thanks for all your help and suggestions.