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Dug into the PTO on my 656 which has never worked since i purchased it.  The fluid is full and i changed the filter.  I am going to change the fluid but wanted to get this fixed before changing in case I have to pull the PTO.  I was hoping the small pin had broke but unfortunately this was not the case.  When you engage the PTO absolutely nothing happens....no sound no trying to start.  So on to the next thing.  Going to try and check pressures if I can get a set-up made with a gauge.  From what I have read 270 lbs is "normal" with no more than a 40 lb drop on to off.  I guess my big question is I see a lot of information/posting about the pressure relief valve.  Everything else on the tractor works so I have a hard time thinking this could be the issue but I am no expert.  My hitch does drop down when not running.  Seems this could be related to a leak in the return line above the PTO?  Can this have that great of an effect on hydraulic pressure to where the PTO would not want to engage?  Any information is appreciated !!!  Thanks!!!

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The PTO has its own pump.   Your pickup tube could have fallen off or the screen plugged.   The threads on the spool didn’t back off so it is not engaging all the way is it??

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8 hours ago, IowaFarmall said:

Dug into the PTO on my 656 which has never worked since i purchased it.  The fluid is full and i changed the filter.  I am going to change the fluid but wanted to get this fixed before changing in case I have to pull the PTO.  I was hoping the small pin had broke but unfortunately this was not the case.  When you engage the PTO absolutely nothing happens....no sound no trying to start.  So on to the next thing.  Going to try and check pressures if I can get a set-up made with a gauge.  From what I have read 270 lbs is "normal" with no more than a 40 lb drop on to off.  I guess my big question is I see a lot of information/posting about the pressure relief valve.  Everything else on the tractor works so I have a hard time thinking this could be the issue but I am no expert.  My hitch does drop down when not running.  Seems this could be related to a leak in the return line above the PTO?  Can this have that great of an effect on hydraulic pressure to where the PTO would not want to engage?  Any information is appreciated !!!  Thanks!!!

The trans filter and other hydraulic functions do not affect the PTO operation at all the pto is its own self contained unit a pressure check is a great first step in no pressure is found and after any adjustments made then its time its pulled sounds like a pump failure or broken parts good luck

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270  psi WAS never normal .   Factory was 185 if you were lucky.  A ne w spool with heavier spring and lock nut could be used but far exceeds the power available on  a 656 and just causes more problems.   

Will. need to pull and repair unit. 

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Thanks everyone!!  Good to know about the top pressure also being lower from the factory. Purchased this from the original owner and according to him he never remembered using the pto so this has me a little worried.  Can anyone recommend a good repair manual?

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4 hours ago, pete23 said:

270  psi WAS never normal .   Factory was 185 if you were lucky.  A ne w spool with heavier spring and lock nut could be used but far exceeds the power available on  a 656 and just causes more problems.   

Will. need to pull and repair unit. 

Pete is correct, if the adjusting nut is not self locking the pressure is 185, if it’s been updated it’ll have a self locking adjusting but and the spec is then the higher pressure.

     On my 656 there’s a shoulder bolt and a triangle shaped piece that is part of the linkage.  Mine was worn and wouldn’t allow the spool valve to come up all the way.  Installed new ones and they made a big difference with the pressure

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7 hours ago, pete23 said:

270  psi WAS never normal .   Factory was 185 if you were lucky.  A ne w spool with heavier spring and lock nut could be used but far exceeds the power available on  a 656 and just causes more problems.   

Will. need to pull and repair unit. 

x2 you don't need 270 185-200 is great plenty

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Picked up everything I thought I was going to need in town today to check pressures.....Came home and pulled the plug and grabbed the wrong fitting.  Also, My PTO has a square block above the valve rod which the on/off actuator rod slides through.  I do not see a "nut" or is that within the housing?

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What I have done in past on the ones with no jam nut, (blue arrow) I have tapped the block on top of spool shaft and put a small allen set screw to use as a lock to keep spool from unscrewing and lowering PTO pressure. 

That hole in spool is what you can insert a small tool to screw it into or out of that top block to adjust pressure.

20200723_220047.jpg

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20 hours ago, IowaFarmall said:

Thanks everyone!!  Good to know about the top pressure also being lower from the factory. Purchased this from the original owner and according to him he never remembered using the pto so this has me a little worried.  Can anyone recommend a good repair manual?

Years and years ago, had a 666 new from factory and pto did not work and somehow the driveshaft and coupler were missing that drive the pto. Just sayin, you purchased from original owner and he never used the pto???  Looks like the square adjusting nut on your spool is threaded on quite a ways and threading it down tighter probably won't make a difference. Kinda looks like time to remove the unit.  Good luck😃

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53 minutes ago, mrfred54 said:

Years and years ago, had a 666 new from factory and pto did not work and somehow the driveshaft and coupler were missing that drive the pto. Just sayin, you purchased from original owner and he never used the pto???  Looks like the square adjusting nut on your spool is threaded on quite a ways and threading it down tighter probably won't make a difference. Kinda looks like time to remove the unit.  Good luck😃

Pop the top link cover off first.  It is only 6 bolts and a whole lot easier than pulling the PTO!!!

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That is the older spool that never had a jam nut. Screwed all the way up the pressure would seldom be over 200 psi. If it is all the way up and pin is not sheared unit will have to be removed. I'm curious of how you determined the pin is alright.

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With the bottom plug out I can pull the handle and the valve moves up and down within the housing.   Everything on the linkage seems tight so I believe the original owner saying it wasn’t used or if it was very seldom.  I am ok with pulling it if I need to but would think it beneficial to make sure the pump is working before I pull it. Is there anything in this unit which could lock up from non-use?

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They are immersed in oil and any time engine is running oil is being pumped through it. So no. What ever is wrong will be revealed when unit is removed and disassembled. The pin is ok. The linkage is moving past the start position. So whatever is wrong will require removal to repair. 

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I'd take an unused PTO that needs something to make it work over a worn out one, for sure!.   Before I pulled the PTO, I sure would take off the top link cover and make sure the PTO drive shaft is spinning....like mentioned above might even be missing.  Will at least let you know if you need to disassemble the unit or not.

Not meaning to hijack the thread, but....I had a 666 that likely has the same PTO.   The PTO works very well, but I have a question for you in-the-know types.   I put a 8' dual spinner Bushhog on it.  With the mower off the ground, tractor ~1200rpm, engage the PTO---there is a horrible racket that sounds like gear teeth sheering, things flying apart, etc for about 2 seconds until the mower blades get spinning.  Its not in the mower, its in the PTO on the tractor.   Then once the PTO is fully engaged, everything works fine... overloading the mower will kill the engine before the PTO slips.  (There is a slip clutch and it does work if you hit something solid).   

I can't start the mower at idle -the motor dies!  It takes a LOT of power to get that dual spinner turning!   SO is that noise something to worry about, or just the clutches chattering until it gets going?

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No doubt!!!!  NOT going to complain about it being not used very much but needing repair!!!  I'm hoping maybe the coupler might be gone or maybe the pick-up tube has fallen off.  I have seen where they don't always attach solid and after 50 years i could see maybe it detatched itself.  Who knows!!!  Guess thats the fun of it all sometimes.  If I really needed it now I might be a little more concerned!!! :)  I don't know the answer to your question but hope someone does.  No worries on "hijacking"!!!!   I enjoy reading and learning what others have experienced.

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15 hours ago, Jeff-C-IL said:

I'd take an unused PTO that needs something to make it work over a worn out one, for sure!.   Before I pulled the PTO, I sure would take off the top link cover and make sure the PTO drive shaft is spinning....like mentioned above might even be missing.  Will at least let you know if you need to disassemble the unit or not.

Not meaning to hijack the thread, but....I had a 666 that likely has the same PTO.   The PTO works very well, but I have a question for you in-the-know types.   I put a 8' dual spinner Bushhog on it.  With the mower off the ground, tractor ~1200rpm, engage the PTO---there is a horrible racket that sounds like gear teeth sheering, things flying apart, etc for about 2 seconds until the mower blades get spinning.  Its not in the mower, its in the PTO on the tractor.   Then once the PTO is fully engaged, everything works fine... overloading the mower will kill the engine before the PTO slips.  (There is a slip clutch and it does work if you hit something solid).   

I can't start the mower at idle -the motor dies!  It takes a LOT of power to get that dual spinner turning!   SO is that noise something to worry about, or just the clutches chattering until it gets going?

PTO gear(s)?

IPTO shaft/couplers?

Center of clutch splines getting loose?

Have you pulled your top link cover to investigate?  Could you rig up a camera to SAFELY observe the noise on startup?

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Well.....Pulled the rear cover.  Coupler is in place and everything seems to be fine.  Going to go ahead and pull the pump out and see whats going on.  Hopefully nothing too severe.  

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Haven’t pulled it but reached my hand down and there was at least a good 1/4” of goop all over the pickup screen and tube. Rear end pretty clean otherwise. Spraying some diesel in to clean and rigged a can and filled with diesel and got the screen all cleaned. Going to keep spraying some in there this week and see if more will loosen up. I’m guessing this was the problem as I have no idea how any fluid could get through. Little hesitant of refilling though......  

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If no fluid could get through, the pump has been starved.  Better just pull it like everyone keeps saying. 

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Usually it boils down to poor maintenance that causes these issues with pumps , pto's or anything to do with hydraulic problems

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On 7/25/2020 at 6:29 AM, 1586 Jeff said:

PTO gear(s)?

IPTO shaft/couplers?

Center of clutch splines getting loose?

Have you pulled your top link cover to investigate?  Could you rig up a camera to SAFELY observe the noise on startup?

I had the same thought, but can't imagine a spline or gear slipping that would not also slip under heavy load (like enough to kill the engine).   The only time the noise happens is on startup.

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