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Discussion Starter #1
Was baling with the 4850 today on one of our Krone 4X4 balers when the PTO just stopped turning. No bang, no ratcheting, no slipping - it just silently quit without warning. PTO lever stayed in gear when it quit and feels perfectly normal. Hooked up a pressure gauge and the PTO pressure is right on spec (a little above actually, right where we set it). The PTO shaft at the rear spins freely by hand with the engine running and shut off but never tries to turn with the engine running.


Has anyone heard of the PTO shaft failing and twisting in two? I would think that it would make a lot of noise if it did but that is what it is looking like happened. I guess we will know in a day or two when we get ambitious and drain all the hydraulic oil out and pull the PTO shaft...


Any other ideas on what could have happened? I have always heard that 30/40/50/55/60 series Deere's had the toughest PTO's known to man...
 

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Never seen it on a 4850 but on a 4630 I have broke about mid way threw trans housing. You should only be able to turn it about a 3rd of a turn with pto off because the pto brake only has 3 splines on it.
 

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take pictures when you start working on it. very interested how it broke as a 4850 is on my short list of tractors that I want in the future. I've bent PTO shafts when lifting a 3 point mounted implement too high, but never broke one.
 

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Discussion Starter #5
I don't think you have to drain the oil, as we don't when we switch the 540 to 1000 on the 4250

Different setup. 4850 is 1000 RPM pto only with a single shaft that runs all the way through the transmission case.


Never seen it on a 4850 but on a 4630 I have broke about mid way threw trans housing. You should only be able to turn it about a 3rd of a turn with pto off because the pto brake only has 3 splines on it.

Agreed on the PTO brake - PTO shaft spins freely like there is nothing but a set of tapered roller bearings holding it.


How did you break the shaft on the 4630? Did you twist it in two or get it in a bind from the implement?
 

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Discussion Starter #6
take pictures when you start working on it. very interested how it broke as a 4850 is on my short list of tractors that I want in the future. I've bent PTO shafts when lifting a 3 point mounted implement too high, but never broke one.

Will do.
 

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The 48S did not have very good pto s at all. When running up to their horse power limit they were weak . Seen several 4850s running forage harvesters , including our own , have a few failures . The splines would strip out of the hub in the clutch pack ( I heard a short zing sound ) ....this is possible what has happened but it should only turn 1/3 of a turn if the pto brake is working . The seal on the clutch pack is known to blow out but you said the psi was good so that shouldn’t be the problem ......it might be a broken shaft as you are guessing ...good luck
 

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Not sure if the 4850 is the same but our neighbor broke the bolts off that bolt the pto drive hub in the clutch on a 4760. 5$ worth of bolts after you split the tractor
 

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Different setup. 4850 is 1000 RPM pto only with a single shaft that runs all the way through the transmission case.





Agreed on the PTO brake - PTO shaft spins freely like there is nothing but a set of tapered roller bearings holding it.


How did you break the shaft on the 4630? Did you twist it in two or get it in a bind from the implement?
It was a customer unit shredding silage bales I just fiqure from the shock loading it finally snapped clean off.
 

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Discussion Starter #10
Not sure if the 4850 is the same but our neighbor broke the bolts off that bolt the pto drive hub in the clutch on a 4760. 5$ worth of bolts after you split the tractor

All large frame 15 speed powershifts are the same as far as I know.
 

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Discussion Starter #11
The 48S did not have very good pto s at all. When running up to their horse power limit they were weak . Seen several 4850s running forage harvesters , including our own , have a few failures . The splines would strip out of the hub in the clutch pack ( I heard a short zing sound ) ....this is possible what has happened but it should only turn 1/3 of a turn if the pto brake is working . The seal on the clutch pack is known to blow out but you said the psi was good so that shouldn’t be the problem ......it might be a broken shaft as you are guessing ...good luck

Was this on all 15 speed powershifts? When you say 48's, do you mean 8 speed 4840's as well?
 

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Over 13K on mine, been no issues. A lot of hours running large PTO combines.
Never heard anyone say there was a common problem either.
Shock loading is murder on any PTO system, so I can see lots of use on a shredder or tub grinder causing issues.

Redneck, with those balers, do you get the surging on the driveline like you do with a small square baler? I know some older tractors run into issues with that in days gone by, but that was with the small balers.
 

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Curious to know what you find out as well, we are big fans of that era of JD units as well. We do our tubgrinding with either a 4640 or a 8640, both have been great. Tried to use our case 9230 on that job too, but burned though two clutch packs and said forget it.

I will ask dad and my uncle if they have any insight on your exact situation. That pto sounds like the 46, only big 1000, whereas our 4240 and 4450 have the interchangeable ones
 

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If it is the shaft, look for an A&I dealer. Did the shaft in a 4640 this spring. Was 1200 from them or 2100 from deere.
 

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Discussion Starter #15
Over 13K on mine, been no issues. A lot of hours running large PTO combines.
Never heard anyone say there was a common problem either.
Shock loading is murder on any PTO system, so I can see lots of use on a shredder or tub grinder causing issues.

Redneck, with those balers, do you get the surging on the driveline like you do with a small square baler? I know some older tractors run into issues with that in days gone by, but that was with the small balers.

The Hesston 4X4 balers surge the tractor a fair bit - it is a slow surge though, and not a shock load, if that makes sense. We have run ens of thousands of bales through the old 4900 Hesstons on our 4650 powershift and never had a problem.


The Krone flywheel weighs 2,000 lbs. (compared to a few hundred on the Hesston) so there is no surge at all but it does take a fair bit more PTO power to run as it's bale chamber is twice as long and will make a denser bale.
 

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Discussion Starter #16
Curious to know what you find out as well, we are big fans of that era of JD units as well. We do our tubgrinding with either a 4640 or a 8640, both have been great. Tried to use our case 9230 on that job too, but burned though two clutch packs and said forget it.

I will ask dad and my uncle if they have any insight on your exact situation. That pto sounds like the 46, only big 1000, whereas our 4240 and 4450 have the interchangeable ones

Quadrange is completely different than 15 speed powershift - I am confident that the quad/synchros are the toughest PTO's known to man.
 

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All large frame 15 speed powershifts are the same as far as I know.
The neighbor was pulling a forage harvester with his 4760 when it just stopped turning. He had a independent mechanic who used to work at deere dealer repair it. Said it was the first time he’d seen it in 30 years of wrenching but now whenever he does a clutch these bolts are replaced
 

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The Hesston 4X4 balers surge the tractor a fair bit - it is a slow surge though, and not a shock load, if that makes sense. We have run ens of thousands of bales through the old 4900 Hesstons on our 4650 powershift and never had a problem.


The Krone flywheel weighs 2,000 lbs. (compared to a few hundred on the Hesston) so there is no surge at all but it does take a fair bit more PTO power to run as it's bale chamber is twice as long and will make a denser bale.
If you are getting that rocking/overrunning motion caused by the back stroke, then that probably contributed to whatever has failed. Back in early days was a problem with some gear driven PTOs in smaller tractors when running small square balers, that motion was sent thru the gear train on each back stroke and eventually things started falling apart.
 

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Can’t exactly recall but the pto went on our 4840 with the 8 speed. But I think it was gear train and was a weakness. A race got loose in the housing and was a complete tear down.
 

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Discussion Starter #20
If you are getting that rocking/overrunning motion caused by the back stroke, then that probably contributed to whatever has failed. Back in early days was a problem with some gear driven PTOs in smaller tractors when running small square balers, that motion was sent thru the gear train on each back stroke and eventually things started falling apart.

Agreed that surging is terrible for most anything mechanical.


The heavy flywheel on the Krone eliminates the surging though so that was not a factor.


My brother and I were discussing it as we were baling last night and came to a conclusion of why the PTO may be weaker than the quadranges. On the Quad, the PTO clutch is on the flywheel spinning 2,200 RPM. On the 15 speed, the clutch is on the driven gear and is only spinning 1000 RPM. 1/2 the speed equals twice the load...
 
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