L3650 PTO problem

[Big Orange]

well seems how there are a lot of guys and gals with way more knowledge about tractors than me perhaps they could point me in some direction.
Hooked up the snow blower today (3 point rear mount) and noticed that the pto shaft from the tractor I believe is slowing down then speeding up while the tractor has the pto engaged? this is a GST model
I don't hear any noise from the transmission but noticed clunking noise from the snowblower due to the speed change.
any ideas on what would cause this? thanks for any help

 

[rbargeron]

Does the pto shaft have a shear bolt at the tractor end? Sometimes a pin can shear but still drives somewhat. With pto engaged and the engine off, try turning the shaft with a bar to see if it slips.

 

[Big Orange]

I looked for a bolt but did not see one. I will check that out tomorrow thanks

 

[rbargeron]

Definitely start by checking out the pto shaft and the snowblower's auger drive shear bolt.

There are more ideas posted on your TBN thread Note that The L3650 with GST has a single main clutch and a hydraulic shuttle, not a 2-stage clutch like other similar models.

If the snowblower "clunks" while running it's possible the tractor's pto gears or shifter parts are damaged. Does it seem normal using the Howse rotary cutter ?

 

[North Idaho Wolfman]

On my L3450 GST if the blower is running unloaded and motor is surging I get some PTO clanking out of the One way clutch, nothing to worry about.

One if the PTO speed is changing a lot but the motor is staying constant, and it drives without surging then look to the implement.
If it surges when it drives then your looking at a bad / slipping clutch disk.
First thing to try is adjusting the clutch pedal linkage.

 

[Big Orange]

I ran the blower tonight with the tractor of course and it almost looks like the blower is surging or free spinning ahead of the pto speed. I went out tonight and loaded it up into a huge pile of snow and it blew the pile away. Yes the engine is running smooth and drives smooth no surging it just seems to be the pto speeding up and slowing down seems to become constant under a full load of snow.
thanks for the help I am going to keep an eye on it.

On my L3450 GST if the blower is running unloaded and motor is surging I get some PTO clanking out of the One way clutch, nothing to worry about.

One if the PTO speed is changing a lot but the motor is staying constant, and it drives without surging then look to the implement.
If it surges when it drives then your looking at a bad / slipping clutch disk.
First thing to try is adjusting the clutch pedal linkage.

 

[Big Orange]

well we have a foot of snow and the rotary cutter is away for the winter but I do not recall any surging in the rotary cutter when I used it last. there is no noise without the blower hooked up and everything else seems to shift and change speeds as well as the clutch does not seem to slip.

thanks for the input I will watch it for now?

Definitely start by checking out the pto shaft and the snowblower's auger drive shear bolt.

There are more ideas posted on your TBN thread Note that The L3650 with GST has a single main clutch and a hydraulic shuttle, not a 2-stage clutch like other similar models.

If the snowblower "clunks" while running it's possible the tractor's pto gears or shifter parts are damaged. Does it seem normal using the Howse rotary cutter ?

 

[Dave_eng]

The one thing I would check is the angle the pto joints are running at.
,
If the shaft is almost horizontal then you have no concerns. If it is at a steep angle the cardan joints, which make up most pto joints, do not like to operate at much of an angle.

If you have a front wheel drive car, the drive shafts which power each front wheel have a "constant velocity" joint which can tolerate turning the front wheels to quite an angle to steer.

The cardan joint was used on the front axles of old 4wd pickups and other similar vehicles. The degree the front wheels could be turned was limited because the cardan joint could not work at much of an angle.

With the cardan joint, if you turn one end of the pto say 15 degrees of rotation, the other end of the shaft will not turn the same number of degrees of rotation. It may be more or less. Over a complete rotation of 360 degrees both ends of the shaft catch up to each other otherwise the shaft breaks. Is is the in points of a complete rotation when you can experience a lumpiness which can produce a speeding up and down sensation especially at lower shaft speeds.

This link to an Alberta government document is much more informative. http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng9924

I dont know why it is not showing up as an active link. To get to the document, cut and paste into your browser.

Dave M7040

 

[Big Orange]

Thank you that makes sense as my pto shaft is at a pretty steep angle while blowing snow, but now that I think about it I think last night I had my pto shaft almost level as it was jacked up with the three point hitch I think (not sure) that it did the same thing?

I guess something else to look at.

The one thing I would check is the angle the pto joints are running at.
,
If the shaft is almost horizontal then you have no concerns. If it is at a steep angle the cardan joints, which make up most pto joints, do not like to operate at much of an angle.

If you have a front wheel drive car, the drive shafts which power each front wheel have a "constant velocity" joint which can tolerate turning the front wheels to quite an angle to steer.

The cardan joint was used on the front axles of old 4wd pickups and other similar vehicles. The degree the front wheels could be turned was limited because the cardan joint could not work at much of an angle.

With the cardan joint, if you turn one end of the pto say 15 degrees of rotation, the other end of the shaft will not turn the same number of degrees of rotation. It may be more or less. Over a complete rotation of 360 degrees both ends of the shaft catch up to each other otherwise the shaft breaks. Is is the in points of a complete rotation when you can experience a lumpiness which can produce a speeding up and down sensation especially at lower shaft speeds.

This link to an Alberta government document is much more informative. http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng9924

I dont know why it is not showing up as an active link. To get to the document, cut and paste into your browser.

Dave M7040

 

[Big Orange]

So another question on this, as I am checking this to see what it is doing I mostly notice the surging speed while idle. Does it matter if I am in neutral on the lever shift or if its in neutral on the gst shift? I think I was testing it while in forward but with the GST in neutral?
really puzzling

Thanks all

 

[North Idaho Wolfman]

So another question on this, as I am checking this to see what it is doing I mostly notice the surging speed while idle. Does it matter if I am in neutral on the lever shift or if its in neutral on the gst shift? I think I was testing it while in forward but with the GST in neutral?
really puzzling

Thanks all

no it shouldn't matter on either being in neutral or not.

I bet what you are seeing or hearing is the "rubber band effect", your spinning an unloaded smooth running implement with only the mass of the blower and probably a combination of the drive setup, PTO shaft joints, and augers, it can cause it to "free spin" then come under load then over spin again.
I also notice this on mine as it's very easy model to spin.
One thing to check is a binding joint on the PTO shaft will cause it to do that.

 

[Big Orange]

Im with you on this one as you might see in my other posts it does seem to be free spinning slows down then surges ahead then starts all over.
I was really concerned my pto was messed up but used it to blow a bunch of snow and seems to do ok. And I thought I was the only one to have one of these blowers.
Thanks Wolfman.

no it shouldn't matter on either being in neutral or not.

I bet what you are seeing or hearing is the "rubber band effect", your spinning an unloaded smooth running implement with only the mass of the blower and probably a combination of the drive setup, PTO shaft joints, and augers, it can cause it to "free spin" then come under load then over spin again.
I also notice this on mine as it's very easy model to spin.
One thing to check is a binding joint on the PTO shaft will cause it to do that.

 

[Dave_eng]

Thank you that makes sense as my pto shaft is at a pretty steep angle while blowing snow, but now that I think about it I think last night I had my pto shaft almost level as it was jacked up with the three point hitch I think (not sure) that it did the same thing?

I guess something else to look at.

If your tilt of the blower is such that the two pto joints are not at the same angle weird effects can happen.

Look at this chart which shows how quickly pto joint life is shortened by increasing angles of operation.

Sometimes there is not much you can do about it but if ever shopping for a new piece of equipment, consider the height of the pto shaft on the blower etc vs the pto shaft on your tractor. Some blowers have bigger fans which means the pto is further above the ground. Other blower models have smaller fans and more blades which lowers the pto

Having an inexpensive infrared temp measuring tool can help in diagnosing many things. A pto joint which is warmer than the one on the opposite end, are all cylinders working hard by measuring the exhaust manifold at each cylinder, are glow plugs all working./...

Amazon has one for about $12
https://www.amazon.com/Nubee-Non-co...=1481775014&sr=8-3&keywords=infrared+temp+gun

Dave M7040

 

[Big Orange]

WOW thanks for the info unfortunately my blower and tractor angle look a lot like the one in the diagram, not much I can do about it? keep the u joints greased up and perhaps lower the shoes on the blower so it does not dig in and release the top link arm some to tilt the blower a little will make a tiny bit of difference but other than that not sure what I can do?

If your tilt of the blower is such that the two pto joints are not at the same angle weird effects can happen.

Look at this chart which shows how quickly pto joint life is shortened by increasing angles of operation.

Sometimes there is not much you can do about it but if ever shopping for a new piece of equipment, consider the height of the pto shaft on the blower etc vs the pto shaft on your tractor. Some blowers have bigger fans which means the pto is further above the ground. Other blower models have smaller fans and more blades which lowers the pto

Having an inexpensive infrared temp measuring tool can help in diagnosing many things. A pto joint which is warmer than the one on the opposite end, are all cylinders working hard by measuring the exhaust manifold at each cylinder, are glow plugs all working./...

Amazon has one for about $12
https://www.amazon.com/Nubee-Non-co...=1481775014&sr=8-3&keywords=infrared+temp+gun

Dave M7040

 

[Dave_eng]

I am posting an image, not to suggest you do it but to get you think how you could change the angle your pto operates at.

Grey market kubotas, which find their way to North America. were often designed and used for roto tilling. In this design, the pto turned the opposite to the ones you are I are used to. Connected to a snow blower the proud owner suddenly realizes his blower is turning backwards.

Years ago there were companies who made external gear boxes for these grey market machines so they would work in North America. Lack of demand has ended the production and easy availability of these gear boxes. Some owners have retro fitted internal components from North American models to their grey market machines but these guys have skills I can only dream of and the cost may be beyond my ability to afford

Innovative owners have come up with solutions like the one in the photo using chains and sprockets to end up with a pto shaft turning the correct way. This same concept could lower a pto height and not reverse the rotation thus improving the pto angles

Dave M7040

 

[North Idaho Wolfman]

Dave_eng,
While I get where you were going with this, that picture is actually a picture of a drive setup to change the PTO from a rear facing to a front facing drive, probably for a front mount blower or a sickle bar mower.
Notice there is nothing but a square shaft end on the bottom facing the rear.

 

[Dave_eng]

Dave_eng,
While I get where you were going with this, that picture is actually a picture of a drive setup to change the PTO from a rear facing to a front facing drive, probably for a front mount blower or a sickle bar mower.
Notice there is nothing but a square shaft end on the bottom facing the rear.

The picture was not intended to have direct relevance to the pto angle problem but rather to perhaps open thought passages that did not exist for the owner. i.e chains and sprockets can provide solutions for problems that you did not consider.

I know your expertise far dwarfs mine and I don't question that.

My observation has been that some new owners don't have any imagination when it comes to an issue they are trying to resolve.

The photo is not even of a Kubota unless I am badly mistaken. Likely it does not have live pto so not so great for snow blowing but I am not absolutely certain of those facts as well.

Dave M7040