Ford NAA Jubilee live PTO

Is there anyone here who fully understands how the optional live PTO works in the Ford NAA/Jubilee? Better yet, has anyone ever had one fully apart? I have the Ford (Dearborn) manual for it. It does not show internal parts. It seems small parts were never available so Ford did not show them in the service manual.

Long story-short. I bought this tractor based on my incorrect assumption is was all gear-drive. When the clutch slipped every time I started the tractor I assumed something HAD to be wrong. I split it and put a new flywheel-clutch into it even though the old one looked fine.

Now I find out that Ford states it is supposed to slip when started cold. I am still kind of amazed that with all the tractors I have worked on in the past 50 years, I had never heard of the Dearborn model 23-12 Live PTO kit before.

When I was working on the tractor, I was at first wondering why Ford put such an elaborate gear-box on the end of the main hydraulic pump just to run the cable for the proof-meter and tach. I now realize it is a tiny hydraulic pump that powers the live PTO package.

What I still do not understand. Ford says that when the tractor is turned off, the hydraulic clutch goes into a "lock-up" mode. I do not understand how this happens? There is a clutch pack, a hydraulic pump, and a control valve that turns it "off" or "on." So when there is hydraulic pressure, the clutch disks engage and engine power gets to the rear differential. When the control valve is turned "off" and no hydraulic pressure gets to the clutches, there is no power to the rear wheels. So far, easy to comprehend. But when the engine is turned "off" and there the hydraulic pump is doing nothing, the PTO assembly somehow goes into a lock-up mode? This is the part I do not understand. What is locking up?

Based on that, I would assume the Live Clutch is spring loaded to the engage position and the hydraulics disengages the clutch.

This may or not help but is all I can find on the subject at the moment. Sorry, I can't link it. "Dearborn Live-Power Take-Off Model 23-12. Installation and Operating Instruction.pdf"

I took one out of a Jubilee. It was missing the little hydraulic pump
completely, so no pressure at all and the tractor worked fine.
Based on that, I think the hydraulic pressure disengages the clutch.
Without pressure, it is engaged all the time.

Thanks for the input. What you have said makes sense to me. Ford does not elaborate on the subject. It seems I just killed mine? I just
changed the hydraulic oil to ATF and now I cannot get it to move at all. It tries a little but does not want to move. I find it hard to
believe the type of oil had anything to do with it. Maybe coincidence? It was sometimes taking 60 seconds before it would try to move on a
cold start. Now it does not move at all. Funny things is this tractor sat outdoors in a junkyard for over 10 years without being run. When
I first got it running - it worked fine. Since then, the more I run it the worse it gets.

I am going to split it. If I see something obviously wrong - like a broken rubber hose or something, I will fix it. Otherwise I am removing
all the optional parts and putting in the conventional long drive coupling like a standard NAA came with. I am wondering now if this is why
this tractor wound up in the junkyard to start with. Looks like it had a new engine clutch. Maybe the last owner had trouble, put a new
clutch in - and then when it was not fixed - gave up? I already have the long coupler to convert it so I guess I will.

Somebody has one of these awful devices for sale on Ebay. Pretty steep price for some old parts that may not even work.

I believe that clutch unit is spring applied and hydraulic pressure released. If you have the coupler to replace the clutch unit with, maybe you could open up the clutch unit and see what?s wrong with it or maybe try pressuring the line going back to it with air or a porta power or other hyd. source and see if you can get it to work before you split it.

I am getting ready to split the tractor. I got the hydraulic control off that runs this aux PTO. To my surprise, when in lockup position, it sends pressure oil to the clutch pack. When disengaged, it cuts off all oil to the PTO clutch. So, now I am even more confused. I guess I am going to find out what is wrong when I get it all pulled apart. If this thing needs pressure to engage the clutch, then I cannot figure how it locks up when the tractor is shut off. If would of been nice of Ford to put some info in the service manual the full theory of operation. I will repost when I have it all torn down.

This would probably shed some light on the subject, can't seem to find the info on the 'net, or any other copies though, dang it!

https://www.worldcat.org/title/part...teering-live-pto-transmissions/oclc/628371906

(University of Guelph, Ontario library.)

I appreciate your keeping us updated. I have 2 NAA?s but neither one has that feature.

(quoted from post at 15:57:36 03/21/20)


Somebody has one of these awful devices for sale on Ebay. Pretty steep price for some old parts that may not even work.


<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto9041.jpg">

Click to expand...

Nice write-up JDEM. Thanks
One of my NAAs has the live pto option, and a combo Sherman.
(It had a loader too, with a front mounted hydraulic pump, which I removed)
If you look closely at the ebay listing (it's still up),
just below the long lever, there is a small blade style switch.
Mine has this too. Turning the blade one way, live pto works, lever forward tractor moves, lever back tractor stops.
Turning the blade switch the opposite way, the live pto lever does nothing. Tractor moves and pulls fine, and moving the lever forward or back does nothing.
By your description, the blade switch must turn off/divert hydraulic flow away from the live pto, making it 'locked up' all the time.(my best guess)

Since mine works fine, I'll leave it be.