broken PTO

oldgrayfellow · May 8, 2010

Tried out my used RS1200 tiller for the first time today, on my YM 186D. Had been tilling my 50 foot garden (soft, sandy loam, no rocks, a few minor roots) for 3 passes, stopping the tiller at the end of each pass.

At the end of the 3rd pass, i raised the tiller, stopped, and clutched to disengage the PTO, to find that it would not disengage. There was no neutral-- i could shift the PTO to high or low speed, but neutral position seemed to have disappeared.

After 5-6 attempts to find neutral i shut off the tractor and took a look at the back, to find milky green fluid running out of the rear end around the PTO shaft. In removing the tiller PTO coupling, i found that the PTO shaft coming out of the tractor had apparently broken loose internally, and could be flopped around from side-to-side by hand.

OK, what the heck happened and why?

And then, what do i do to fix it? I have the service manual, and am willing to tear into it, but it would help a bunch if somebody could tell me the most likely problem and the best way to go about it.

Thanks loads.

winston1 · May 8, 2010

Without tearing in there it would be hard to know just what all is wrong. I would guess your pto shaft bearings have disintegrated. Different model, but the manual for a ym220 just shows the whole unit coming out. If you have the manual I don't think you will get much better instructions. Sounds like you have water in your fluid, I would look all around in there as much as is possible when you remove the pto assembly for other possible damage. Of course you are looking at fluid, strainer clean and new filter. Hopefully, your gears and shafts will be OK. Good luck.

oldgrayfellow · May 9, 2010

Well i pulled apart the PTO today; the only thing broken or damaged i can see so far is that a thin metal ring (a keeper ring of some sort?) was spread/broken/twisted and out of place (see photo # 2635).

The whole PTO shaft had slid forward (toward front of tractor), apparently because the forward bearing (near top center in the photo) had slid out of its bore in the casting. You can see the forward bearing out, slanted and above the plane of the casting near top of the photo (sliding forward equals sliding "up" in this picture).
There is a groove in the outer race of this forward bearing. Seems like it might be for a circlip that would prevent the bearing sliding forward this way, but no circlip was present, nor did any appear to be lying in the transmission housing.

The split/twisted metal ring (near the point of the bamboo skewer) seems too thin to have been a keeper ring-- too thin for the width of groove in the bearing. (The groove is visible near the bottom edge of the bearing, above the plane of the casting in the photo.

In photo #2645, I have slid the bearing back partially into its bore, and the point of the bamboo skewer is resting in the groove.

In photo 2642 is the receiver cap with seal (looking at inside face of cap). When the shaft slid forward during the incident, fluid leaked around it past this seal.

Photo 2632 is inside of the transmission, after removal of the PTO unit

So, does anyone know:

1) if there should be a circlip for that groove, or if not, how is the PTO shaft held from sliding forward through the bore as it did.
2) what are the function and proper location of the existing damaged thin ring
3) what else, if anything, i should check. (The bearings, gears, shafts, and everything else i can see looks undamaged and untouched.)

Thanks

winston1 · May 9, 2010

You are pointing at the retaining ring from the bearing. Have to wonder why it came out. Any big impacts on the pto? May be an H6207snr bearing. If the ring is to thin for the bearing it could only be from the bearing turning in the housing and wearing the ring down. I can't tell from your pictures if it has turned in the housing. I'm assuming not if you believe it to be ok. I would examine the bearing and ring closely and make a decision of whether it needs replacing or not. The ring is what keeps the bearing from going forward. By the way, that is an excellent picture of the differential lock, very interesting.

1danny · May 9, 2010

oldgrayfellow said:
Tried out my used RS1200 tiller for the first time today, on my YM 186D. Had been tilling my 50 foot garden (soft, sandy loam, no rocks, a few minor roots) for 3 passes, stopping the tiller at the end of each pass.

At the end of the 3rd pass, i raised the tiller, stopped, and clutched to disengage the PTO, to find that it would not disengage. There was no neutral-- i could shift the PTO to high or low speed, but neutral position seemed to have disappeared.

After 5-6 attempts to find neutral i shut off the tractor and took a look at the back, to find milky green fluid running out of the rear end around the PTO shaft. In removing the tiller PTO coupling, i found that the PTO shaft coming out of the tractor had apparently broken loose internally, and could be flopped around from side-to-side by hand.

OK, what the heck happened and why?

And then, what do i do to fix it? I have the service manual, and am willing to tear into it, but it would help a bunch if somebody could tell me the most likely problem and the best way to go about it.

Thanks loads.