Telescoping PTO Shaft: Which end to tractor?

[mitchfielding]

Hi all, just hoping for a bit of insight.

I have a BareCo PTO shaft for my slasher which I've recently disassembled to grease. On reassembly, I can't recall if the yoke on the outer tube goes to the tractor end, or the yoke on the inner tube goes to the tractor end. It's obviously important since the BareCo PTO plastic protector sleeve is marked with <----- 'Tractor End'.

My manual doesn't help and searching the net for 4 hours reveals any and all combinations. Some tractors have the inner 'thin' tube of the PTO shaft attached to the tractor's PTO, others have the outer 'fat' end connected to the tractor. My gut says fat end to tractor but happy to be wrong.

Appreciate your advice !

Mitch

 

[gtrippleb]

On my post hole digger the yoke on the inner tube connects to the tractor. Does the PTO shaft have a button that you push in so you can slide the yoke over the PTO stub either on the tractor end or the implement end?

 

[DT86]

I'm having a hard time coming up with a reason that it shouldn't work either way.

 

[mitchfielding]

Interesting gtrippleb - it's the inner shaft in your case.

Yes, I have a spring button on either end to lock the splines onto the PTO shaft and implement transmission shaft. There's no difference between the yokes or splines at either end. So you can easily end-for-end the shaft and it works fine. Just wondering which is the 'right' way?

Thanks for your input.

 

[mitchfielding]

I agree DT86. I'm baffled because the 'Tractor End' is clearly marked on the plastic PTO guard. So out of the factory, the shaft's direction is designed to be a certain way, at least from the manufacturer's standpoint.

 

[MBTRAC]

The "theory" is the inner tube should be connected to the implement, the outer tube should always be connect to the tractor.

 

[mitchfielding]

Thanks MBTRAC, that's along the lines of my thinking. Just wish I knew the rationale behind it. And now I'm wondering if you run a PTO with the inner tube's yoke connected to the tractor like gtrippleb does, what are the implications or risks? Is it somehow a weaker or less robust setup?

Any more guidance from the tractor gurus out there?

 

[greg_g]

Larger PVC tube (cover) belongs on the PTO end. Consider (a) that the tractor end is generally higher than the implement and (b) water runs downhill. With the upper half overlapping the lower half, water stays outside. Regarding the steel tubes, consider that torque is delivered by the PTO. The larger cross section will absorb more shock load than the smaller cross section. This is especially true with electric PTOs. Hence the larger half typically goes on the drive end, and the smaller half on the driven end.

//greg//

 

[gwdixon]

All good answers in theory. But....on PTO shafts where you don't have a choice (like with a slip clutch or bolt-on yolk to the implement) the smaller diameter tube is on the tractor's side IIRC. Maybe someone can correct me if I'm wrong - but it is a good gauge for the correct answer.

Rain or water on the PTO shaft is more likely to happen when the shaft is OFF the tractor and just sitting there dangling down. Thus, the narrow diameter should go on the tractor's side.

At any rate, I always store a PTO shaft in two pieces so it doesn't stick or rust together. A grinder is used to put a little dimple one shaft surface (each side) where they connect so the shafts will line up and slide together the first time. This is because some shafts only fit together one way - and it is never the first way you try for some reason!

 

[KYErik]

On my implements, the male (inner) half of the telescoping PTO shaft hooks to the tractor and the female (outer) half is connected to the implement gearbox. As others have said, this orientation does keep rain water from running into the gap between them when the implement is unhooked and the PTO shaft is hanging down.