Over-running Clutch For PTO Inside The Tranny?

[npalen]

So…does this mean you can’t start a modern compact tractor by rotating the PTO shaft?
Can’t find the video anymore of a guy who coiled a fire hose around the rotary mower PTO shaft and then connected it to the family car and had his wife drive away. The tractor started right up. I thought it was a pretty slick way to “pull start” a hydro.

Does this also mean you can’t turn your PTO on (with the engine off) to “lock” the PTO in place. I do this and manually turn the rotary mower blades to confirm that the mower’s slip clutch “slips” and isn’t rusted together. ….or do you just turn the PTO off and rely on an internal PTO brake?

Interesting! My roto tiller has a slip clutch but the tractor's over-running clutch will "slip" much easier than the slip clutch as shown in the short video above.
I would assume that the guy starting his tractor with a fire hose )) did not have an over-running PTO clutch in his tractor.

 

[npalen]

I always thought the overun clutch was there to keep from burning the PTO brake up.

That would seem to be at least one reason for the over-run clutch. The plot thickens.

 

[ptsg]

That would seem to be at least one reason for the over-run clutch. The plot thickens.

But then, what's the point of having a PTO brake in the first place? The over run clutch will make it pointless.

 

[npalen]

But then, what's the point of having a PTO brake in the first place? The over run clutch will make it pointless.

True that.

Edit: So what exactly happens with a PTO brake when a large over-running load such as a rotary mower or snow blower is shut off? Does the brake slip and gradually slow and stop the load or is it nearly instantaneous?

 

[npalen]

Anyone else aware of an internal over-running PTO clutch on their tractor? (I realize that some might be unaware of it)

 

[Fordy20]

On my 620 two cylinder John Deere and on my 4020 there's a PTO brake so when the the tractor is running and the PTO is not engaged it can't be turned by hand making it difficult to match the splines when you hook up a PTO implement such as my flail mower. On my 5045E John Deere, you can turn the PTO by hand to match the splines on the implement PTO which sure makes it a lot easier.

 

[Hay Dude]

True that.

Edit: So what exactly happens with a PTO brake when a large over-running load such as a rotary mower or snow blower is shut off? Does the brake slip and gradually slow and stop the load or is it nearly instantaneous?

The brake gradually stops the load. if you make a habit of turning off the PTO at high speed, the wearing out process happens much faster.
Throttle down before you hit the PTO button.

 

[npalen]

I would think that an over-running clutch on a hydrostat tractor would not be needed and wonder if its just a matter of the same PTO components being used as on a gear drive tractor. I can't imagine that the PTO could overdrive the hydrostat.

 

[npalen]

On my 620 two cylinder John Deere and on my 4020 there's a PTO brake so when the the tractor is running and the PTO is not engaged it can't be turned by hand making it difficult to match the splines when you hook up a PTO implement such as my flail mower. On my 5045E John Deere, you can turn the PTO by hand to match the splines on the implement PTO which sure makes it a lot easier.

What happens if you try turning the PTO backwards (counter-clockwise) with the PTO engaged? (With the engine off, of course) Is there the sound of a over-running clutch?

 

[npalen]

I'm surprised that more of the TBN gurus have not chimed in on this discussion. I'm guessing that many are not sure whether or not their tractor has an internal over-running PTO clutch or whether they have even heard of such a thing.