1972 Ford 4000 w/select o speed-ptodetent

[AA III]

I have a 1972 Ford 4000 LCG tractor. It has the Select o speed transmission. I can't find any info for the PTO detent (to keep the PTO engaged). PTO works fine but I have to continuously pull on the PTO handle to keep it engaged. I have a manual for the tractor but it doesn't show/tell me anything about what keeps the PTO engaged. Does anyone know how it works?

 

[Bern]

Make sure you're getting the maximum travel of the lever as per the dimension in the manual. If the internal linkage bottoms out before the handle reaches the detent, you'll have that problem.

 

[Sean in PA]

(quoted from post at 13:21:27 04/06/23) Make sure you're getting the maximum travel of the lever as per the dimension in the manual. If the internal linkage bottoms out before the handle reaches the detent, you'll have that problem.

It's not a lever on that model. It's a handle on the dash attached to a cable that goes down to the top cover of the trans. There is no detente. You pull out on the handle to engage the PTO and push it in to disengage. All it does is open a valve on the control valve block in the transmission to supply flow and pressure to the PTO clutch pack. The PTO handle on my '73 4000 w/S-O-S stays where it's put when I pull it out. It engages the PTO nice and strong. The only issue with mine is there is no PTO brake on that model, and so it spins slowly when the handle is pushed in, even with a brush hog attached, though much slower than without the brush hog attached, and a piece of 2x against the PTO will stop it when the handle is in. Perhaps the cable isn't adjusted properly. Follow the procedure in the service manual to adjust it properly. If the handle still slides in after you pull it out, the next step would be to pull the top cover to see what may be wrong with the valve or linkage inside. Be sure to follow all of the steps in the manual when removing the top cover, otherwise you might do something that costs you time or money or both.

 

[AA III]

Thank you for the info. I had a friend of mine look at the internal linkage and there was a bend in part of it that did not allow it to fully travel as it should.

 

[AA III]

Thanks for the info Sean. I did have a friend inspect it, we found a bent piece on the internal linkage and fixed it. It now appears to fully open the valve in the transmission. When I get around to putting it back together I will make sure that it is within the 1-3/8" to 1-7/16" amount of travel that is specified in the repair manual.

 

[Bern]

I meant handle, not lever. And yes, it does have a detent. On the last one I had out you could definitely feel a ball and
spring arrangement at the ends of each travel. It has to have a detent, because if it doesn't the vibration of the
machine, along with the internal spring trying to push the spool back into the off position will eventually allow it to
creep back, which is not good if the handle is mid-travel and the PTO is under a heavy load.

 

[AA III]

(quoted from post at 14:53:26 04/06/23) I meant handle, not lever. And yes, it does have a detent. On the last one I had out you could definitely feel a ball and
spring arrangement at the ends of each travel. It has to have a detent, because if it doesn't the vibration of the
machine, along with the internal spring trying to push the spool back into the off position will eventually allow it to
creep back, which is not good if the handle is mid-travel and the PTO is under a heavy load.

That sounds right because it looks like there is a piece missing in the handle, thanks

 

[Sean in PA]

(quoted from post at 17:53:26 04/06/23) I meant handle, not lever. And yes, it does have a detent. On the last one I had out you could definitely feel a ball and
spring arrangement at the ends of each travel. It has to have a detent, because if it doesn't the vibration of the
machine, along with the internal spring trying to push the spool back into the off position will eventually allow it to
creep back, which is not good if the handle is mid-travel and the PTO is under a heavy load.

Well mine has no noticeable detente position in that it doesn't click when it is fully engaged, and it holds position once fully engaged and never moves from the vibrations of the tractor. Maybe there is a detente down in the valve, but it is not detectable from the feel of the handle.

 

[Bern]

The detent is definitely in the handle, not in the valve. You can clearly see it in the pics below. You can see the shiny
detent ball through the hole in the washer, and a spring as well if you look off to the side using a flashlight.

 

[Greg NE]

Bern is correct, there was a detent built
into the handle assembly when it was new.
There was a ball bearing with a spring
behind it built into the upper part of the
shifter cable assembly when it was new. It
functioned by engaging the two notches in
the shaft behind the handle. The problem
is after a lot of use it wears a groove in
the shaft and the detents kind of disappear
and no longer keep the pto fully engaged. I
have had that happen on a couple of my
tractors. The easiest fix I came up with
was to clamp a small visegrip to the shaft
to keep it from moving to keep it from
vibrating in.

 

[AA III]

Thanks for all the info. I thought the detente was built into the handle too. We took the handle apart and tapped the hole so that a small winged bolt can be threaded into it. That should hold it in place and be easy enough to disengage with just a quick 1/4 to 1/2 turn on the wing. Thanks again everyone!