PTO's shafts ARE NOT designed to last forever.

[MapleLeafFarmer]

OK.... I admit I have a lot of really old pto's around my yard site / sheds. And when I mean old I mean > half century old. I like to make regular maintenance but hate replacing stuff that still works.

So today i buy a new snow blower. Came with PTO too long so a simple shortening required. Done this many times. So I take my measurements, consult the manual and find the following chart.
I must say I am a little taken aback. I would go broke if I replaced my PTO at the rate the manual indicates.....

and being totally truthful, I likely exceed these numbers by 10x - 20x fold in some instances

how about you folks??

so to increase the lifespan of the pto shaft I will push the blower to its farthest back setting and cut accordingly as the farther back the implement is set to lower the angles of attack are so lifespan should increase.

 

[NCL4701]

In my experience, which is admittedly anecdotal, the hours in that chart would likely be accurate if you never once greased the U-joints. Keep them greased and they should last much longer than that. I do minimize offset angle to the degree practical.

To me, they’re kind of like tires, loader pins, and quite a few other items: replace when they wear out, not when some hour milestone hits. I run them until the bearings in the U-joints have excessive play. Not too hard to feel play in the U-joints when the shaft isn’t attached to the tractor. Like you said, that’s usually at least 10x the numbers in that chart. If the caps are still tight in the yokes, the crosses can often be replaced more cost effectively than replacing the whole shaft. If the yokes get wallowed out or the correct crosses can’t be sourced, it’s time to replace the shaft.

That and there’s not much difference between the U-joints on a tractor PTO and the U-joints on light and medium duty truck drive shafts. I can’t imagine anyone finding a 450 hour life on the U-joints on their truck being anywhere near reasonable.

That’s just my experience. As always, YMMV…

 

[DaveD]

For those of you who have mid-mount mowers, take a look at the angle of the PTO shaft driving the mower when it is down at a lower setting. It's got to be 25 degrees or more on mine (I haven't just taken a look at it; this is what I recall) and it has lasted the 30 years and 1400 B1700 tractor hours of mostly mowing grass and high weeds. I've greased the U-joints on an average of once a year. They are still tight and completely functional.

 

[Bmyers]

PTO shafts need to be replaced?

I don't remember ever replacing a PTO shaft on anything. I know I helped grandpa replace the u-joints in PTO shaft, but I don't know of a shaft ever being replaced.

 

[Grandad4]

Probably also has something to do with where they come from. Not hard to imagine a wide range of manufacturing quality.

 

[mikester]

Is it the shaft or the bearings that need replacement At those hours?

 

[JonM]

OK.... I admit I have a lot of really old pto's around my yard site / sheds. And when I mean old I mean > half century old. I like to make regular maintenance but hate replacing stuff that still works.

So today i buy a new snow blower. Came with PTO too long so a simple shortening required. Done this many times. So I take my measurements, consult the manual and find the following chart.
I must say I am a little taken aback. I would go broke if I replaced my PTO at the rate the manual indicates.....

and being totally truthful, I likely exceed these numbers by 10x - 20x fold in some instances

how about you folks??

so to increase the lifespan of the pto shaft I will push the blower to its farthest back setting and cut accordingly as the farther back the implement is set to lower the angles of attack are so lifespan should increase.


View attachment 180995

that is not 450 hours of tractor time its runtime of the pto itself. it is a chart showing how long its expected to live when not level to the output shaft. so if your implement input is level to the tractor output then it should last a lot longer than 450 hours if your maintaining it.