PTO over run clutch question

[smack957]

My little tractor has an internal PTO over run clutch. My question is can they slip? I bought my tractor used and the first time I tilled with it, I hit some rocks. My shear bolt did not shear, but the tiller and pto shaft stopped turning momentarily and started back up again once past the rock. This was at 540 rpm. At low rpm and slower tiller speeds, it did not have this problem. The HST did not stop moving the tractor forward, so I don't think the main clutch slipped. I ordered a new shaft with a slip clutch, but just wondered what would have been the cause of the slip. Hoping its not a major problem.

 

[Jerry/MT]

My little tractor has an internal PTO over run clutch. My question is can they slip? I bought my tractor used and the first time I tilled with it, I hit some rocks. My shear bolt did not shear, but the tiller and pto shaft stopped turning momentarily and started back up again once past the rock. This was at 540 rpm. At low rpm and slower tiller speeds, it did not have this problem. The HST did not stop moving the tractor forward, so I don't think the main clutch slipped. I ordered a new shaft with a slip clutch, but just wondered what would have been the cause of the slip. Hoping its not a major problem.

Too much torque for the clutch pack to resist probably was the cause. Some of these are pressure actuated using the hydraulic system.

I would advise a slip clutch on the tiller to save wear and tear on the internal pto clutch. I have an independent pto on all our tractors and I use an external overrunning clutch on my rotary cutter as well as the slip clutch on the cutter.

 

[Roadworthy]

You state your tractor has an internal overrun clutch. I'm curious. How do you know this? Is it somewhere in the tractor literature?

 

[Sawyer Rob]

I have no idea what tractor you have, but all the overrun clutches I've seen were steel ratchet clutches, they can't slip unless they are broken and then they "slip" pretty much all the time. In other words, "one-way clutches".

Maybe the chain in the tiller jumped the gears from being too loose? Maybe it slipped the splines??

Is the sheer bolt the proper size/grade? OR did someone put a stronger bolt in it??

I always run my tillers at pto speed! Yes, it does make a difference.

SR

 

[old and tired]

Number one thing we need to know is What tractor do you have?

If it's an early version of Kubota L2800 or L3400, 2004-2005. Tillers have taken out several of the ratching PTOs. Mine started to skip here and there, I sold the tiller.

Let us know which tractor... there a good write up on how to repair / change out to the new style of PTO CAMS.

 

[smack957]

I have a 2014 Mahindra Max 22 HST. I bought a service manual and saw that there was an overriding clutch. I bought a new pto shaft with a slip clutch and while I was trying to dial in the pressure to get it to slip before the pto itself did, I noticed that each time the pto itself would stop turning, there was an audible "click". Not sure what that means. Once I got the slip clutch set, the pto itself did not do it anymore. But the pto definitely has something really wrong. Guessing that is why the previous owner sold it?

 

[Roadworthy]

I did some research. Yes, your tractor could (and probably does) have an internal overriding or overrunning clutch. It should not normally slip driving a PTO implement. If the implement exceeds the pto speed it will slip at that point to prevent the implement from driving the tractor forward. If yours slips attempting to drive the PTO implement you may indeed have a problem with it. Hopefully it's in an easily accessible location and easy to replace. You should check it out or have it checked out more thoroughly.

 

[old and tired]

...Guessing that is why the previous owner sold it?

Not cool when that happens.

I was looking for the thread about replacing the over-riding cams; but can not find it.

 

[smack957]

Thanks all! At this point, I will only be tilling a few times a year, so hopefully I can nurse it along for a while. It looks like that clutch is inside the transmission, so it may be hard to replace.