Jinma 254 pto engagement

[Whenu]

Hi all, nice to be here.
I'm having a problem with the engagement of the 540 revs speed of my pto, it seems to be not not engaging properly and jumps out. It engages the 1000 revs speed ok.
The clutch is adjusted to the manual specs.
Is it possible for the gears to have moved or been pushed forward on the shaft? I've had to untangle pampas grass from the shaft before.
Trying to find a solution without having to take the top of the gearbox off.
Thanks for your time.

 

[piper184]

That is interesting. My 284 won't stay in the 1000 RPM setting it keeps popping out to neutral. 540 works fine. Since I don't use the 1000 setting very often my solution is to use a bungee cord to hold the lever where I want it.
I suspect that the sleeve that slides back and forth to choose the speed is not fully engaging the selected gear. This could be due to several things and I have not been inside the rear differential for troubleshooting. A bent fork or poor assembly of the parts may contribute to misalignment somewhere. Another possibility is the detent at the control lever is too weak to hold it in the set position.
I doubt that the clutch would have any effect on the gear selector. I hear you on the trying to avoid digging down to into the gearbox, it is quite a pain. I did it once to diagnose a differential lock problem only to find out it was a loose bolt at the outside of the lever.
There is what appears to be a thrust washer at the front end of the PTO shaft. Perhaps it has too much or too little play and is effecting the meshing of the gears, but you we would have to take it apart to look at it.
Hopefully someone who has dug into this issue before will chime in with advice.

 

[Whenu]

Thanks Piper, thought I had it sorted by cleaning around the detent but it still wasn't engaging properly.
Started cleaning the outside ready for delving in this weekend.
For a reference, I ve attached an exploded view.

 

[piper184]

Same set up as mine. Please let us know what you find.

 

[Whenu]

have found out the teeth on the 50T gear are worn, and presume the teeth on the slider are worn as well.

 

[Agvg]

Are they so worn that it's a problem? Doesn't seem to bad on the picture.

 

[Whenu]

Are they so worn that it's a problem? Doesn't seem to bad on the picture.

Think the internal teeth on the sliding mesh gear are pretty worn too.

 

[ptsg]

When you engage the 540, does the slider engage fully with the narrow teeth? It almost looks that the slider is not moving the full travel and its barely engaging the narrow teeth.

Right now it's on 1000 RPM for the picture, right? So we can the see the shape on the teeth for the 540. The 1000 does seem to engage fully.

 

[piper184]

The teeth look about normal for a synchronizer used in a manual transmission. Tapered on the slider side to aid during engagement. Your gear looks about the same of the picture of a new one I found online. 184.37.457 (5 T Gear for Rear Axle) | Jinma Tractor Parts, Farm Pro Tractor Parts | Circle G Tractor Parts

See if you can get a good look at the inside of the slider with a mirror or something. Also, check for full travel and engagement with the 50 tooth gear. Something doesn't seem quite right here....

 

[piper184]

One other thing, it may just be the lighting but the oil seems kind of milky looking, which might indicate moisture in the oil.

 

[Whenu]

The other pto gear for comparison. The slider moves to the full range, but when selecting 540, the shaft can still be moved whilst the slider is part way along the gears. on the 1000 gear as soon as the slider moves over the gap between the gears, the gears mesh.
Yep, the oil has had a bit of moisture in.

 

[Whenu]

With selector in neutral.

 

[piper184]

Well there is definitely more wear on the 540 side. It will be interesting to see what the inside of the slider looks like. If you decide to replace the 540 gear it might be a good idea to at least order the slider so you have a new one for comparison. Associated thought, I wonder if you could "flip" the slider so the other side engages?
Let us know how it goes it is good information for future users.

 

[Whenu]

Well there is definitely more wear on the 540 side. It will be interesting to see what the inside of the slider looks like. If you decide to replace the 540 gear it might be a good idea to at least order the slider so you have a new one for comparison. Associated thought, I wonder if you could "flip" the slider so the other side engages?
Let us know how it goes it is good information for future users.

Have orders both. Will see how far the excess wear on the slider is.

 

[ptsg]

Have orders both. Will see how far the excess wear on the slider is.

From what I gather from the pictures, my best guess is that the slider wasn't engaging fully on the 540 side and started wearing out the tip of the teeth on both the gear and the slider. Now it just pops out of gear.

 

[Whenu]

Yep, ptsg, think that's what was happening.

Anyone have taken the pto shaft out before?
Looking at making a plate with tapped holes in, to go over the pto shaft, and pull the bearing and shaft out. Using the pto coupling as an anchor to push against.

 

[piper184]

It looks like the only thing holding the PTO shaft in place is the rear bearing. Remove the outer cover and the seal and bearing come with it. I have replaced the seal before but that is far as I had to go.
After that, I think you can just pull on the PTO shaft and it should slide out and each of the pieces on that shaft will fall off one by one. There does not appear to be any snap rings or other method of retaining shaft in place except a ridge on the shaft that rides on the outer bearing. There is a (thrust?) washer on both ends of the shaft, maybe that is all that keeps it in place.
I wonder if wear on the rear washer allowed the 50T gear to ride farther to the back of the case than designed and that lead to the condition where the slider could not fully engage?
Before you remove the outer bearing cover it would be interesting to see how much end play there is at the PTO shaft and at the 50T gear.

 

[Whenu]

Thought the bearing was housed in the cover and would come out when removing the cover, but it's in the housing. There's no end-play on the shaft and gears.
The large 50t gear, once off the shaft, does it just slide around and get past the wheel drive gears?
Figured that the gears would have to be slid, carefully, off the shaft when withdrawing the shaft.

 

[piper184]

It is good that you have no end play. I checked my PTO shaft today and it does not have any end play either.
This seems a little weird because you wouldn't expect the ball bearings on the output shaft to act as thrust bearings and if they did you would expect at least some detectable end play. Otherwise it would indicate they were pre-loaded and that is not good for ball bearings. So there must be something else holding all this together but I see no indications of anything in the parts book.
On the single speed PTO tractors there is a castle nut and cotter pin on the inside end of the PTO shaft that holds it all together but the two speed does not have that. Something is taking up the slack, but what?
Hopefully the 50T gear will clear the upper shaft and you won't have to take it out.
You might try putting a rod or screwdriver in the hole at the end of the PTO shaft and tapping with a hammer to see if you can get the shaft to back out and bring the bearing with it. It may be a friction fit and not a press fit.
Hopefully someone who has actually done this before will chime in with some "how to's".

 

[Whenu]

Have taken the upper shaft out already, not a problem, did the bearing on that a few years ago. The cast-iron fitting for the bearing is awkwardly placed.