Zen-noh Yanmar 22-24 transmission problem

[ibldrc]

I'm working on a Zen-noh Yanmar, either a 22 or a 24. The Zen-noh labeling says 22 but the gauge cluster says Yanmar 24. I'm not concerned about which one it is at this point. The engine runs fantastic, and it's in fair overall shape other than the gear problem. I know parts may be scarce, in fact my original reason for the purchase was strictly for the engine, but I'm thinking maybe we can save this one. It would be a shame to part it out, as it's still in good shape.
I've taken some pics, and done some initial troubleshooting, and here's where we're at:
Engine running:
The clutch works, the PTO drive works in all gears.
I have been able to get it to move in gear for about a foot, but with no consistency. I'll have to push it by hand a bit, then it will move and stop.
With both shift levers in neutral, clutch engaged, it will knock a bit, like something is floating around in there getting kicked about.
No abnormal noises with clutch depressed.

Engine off, decompression lever engaged, clutch engaged, and gearbox top cover removed:
At least one broken tooth in what I think is second gear, see below.
With the rear tires raised, RH gear shift in neutral:
LH gear shift in first, moving the wheels together to lock the diff, there is no movement.
LH gear shift in second and third, the upper LH "inside" shaft will spin when the wheels are turned together by hand, and a timed knocking can be heard and felt.
here are some pics and video link (tried to upload but too big):
YouTube

 

[California]

I see one thing you didn't discuss: That left hand outboard reduction gear, by the tire, looks like it is sealed with RTV liquid gasket indicating it was opened up in the past.

Could there be a jammed gear fragment in there? Does the tractor roll easily in any shift position?

 

[winston1]

If you can't course the noise I would remove the hydraulic lift housing and have a look at the differential area.

After reading back through it sounds as though you believe the knocking or noise is from the transmission gears, if so, maybe drain the fluid for a closer look? Maybe you have already done that?

Not for sure but this may be the gear with the missing tooth. Yanmar 194555-2516 Sailboat Supplies, Engine Parts and Boat Parts

 

[spokane 1]

the knock is probably the broken gear even if the rig is in neutral,,,,, the gears will still turn and engage the other drive gears on the main shaft. the slight misalignment allows for a knock as the gears almost collide top to top. its probably best not to run this until that gear is removed.
if there is no parts you can remove this gear entirely and place a spacer on the shaft and reinstall it. You just won't have 2nd gear.

 

[ibldrc]

If you can't course the noise I would remove the hydraulic lift housing and have a look at the differential area.
[/url]

Giving this a go, I've gained access, cleaned it up a bit, and I'm ready to lift it off, will do that tomorrow after work. Will there be any surprises? Anything that's going to come out of wherever it belongs and be difficult to figure out afterwards? I'm thinking the best way to lift it off is with my engine hoist from the cross brace holes... any opinions (it looks like it's gonna be heavy)?

 

[spokane 1]

yeha you know I looked at your photo a lil closer it seems your broken gear is on the main thru shaft...all your shifting is done on the other shaft.
you wont be able to remove this broken gear and repair with a spacer. you'll lose all thru power.

Last I dealt with a yanmar was about 30 years ago. Back then all the parts were available but it took awhile 1 month to ship.. before you spit this tractor.....why don't you shop a bit and see if the parts are available
In my neck of the woods Portland was just building a scrap pile of Korean tractors in the 1990s. think it was out by Hillsboro.
these parts take a bit to get. i replace the entire reverse idler and shifting fork on that job.

for future reference.
the front half of the tyranny is called the shifting shuttle. the rear end that houses the wheels is called the tyranny. (only in tractor talk)

locate some parts then start ripping. is my advice.

 

[winston1]

Nothing will come out when you lift it off. I removed one on an FX24D by hand. I am not a weight lifter, probably average strength. I will confirm it is heavy. If available a hoist is a good idea. A picture of the differential area under the hydraulic unit.

 

[clemsonfor]

I lifter the one off my ym2000 i too am average strength for my age. It is heavy but also it is liftable by hand. I lifted mine off as well. A hoist would be not effort though.

 

[careyo63]

Any parts available yet? I hope it doesn't ends up getting put back together with the bad gear. And other things come to find. Or a parts tractor. Nothing of the two in my area 22-24.

 

[ibldrc]

Good news, I suppose. it can't be "bad" since i bought it broke.
It's not the ring and pinion, and it's not a main shaft. Here's what I found; There's an "intermediate" set between the fwd and rear sections, and I can see one tooth broken on the shaft gear, and a series of teeth gone on this "intermediate" gear.






Everything else seems to be in fine shape. Glad I chose to fix it. Lots of life left in this machine.

If I had to I could weld the single tooth and reshape it, but this top one that's missing numerous teeth looks to be cast, so I'm going to have to source it and replace. Aaron at Hoye has already sent me parts diagrams, so we'll get back with them and see how it goes.... Lightning fast response with their work tickets by the way.... very impressed with the C/S there!