PTO not staying on New Holland 8340

P

paddy farmer

Active Member
Good evening. I am having trouble with PTO . The problem is that after switching pto on it stops almost immediately. Sometimes it stays on a little longer. I have fitted new switch but no improvement.I have also looked at relay under magnifing glass and i think all looks ok but I no expert on relays.Please help
 
paddy farmer said:
Good evening. I am having trouble with PTO . The problem is that after switching pto on it stops almost immediately. Sometimes it stays on a little longer. I have fitted new switch but no improvement.I have also looked at relay under magnifing glass and i think all looks ok but I no expert on relays.Please help
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Is your alternator charging ok?
 
paddy farmer said:
i think so MF 30, but i will check it tomorrow thank you
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If it isn’t charging or the volts drop below around 13 volts the PTO will switch off. Like a magnetic switch to make sure the PTO won’t restart as soon as the engine is started if the PTO switch is left on.
 
MF30 said:
If it isn’t charging or the volts drop below around 13 volts the PTO will switch off. Like a magnetic switch to make sure the PTO won’t restart as soon as the engine is started if the PTO switch is left on.
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good evening MF 30 I checked alternator today and its charging to over 14 volts. The switch for the pto is the push down and twist type and stays in the ON position even though the pto only comes on for about a second and goes off
 
paddy farmer said:
good evening MF 30 I checked alternator today and its charging to over 14 volts. The switch for the pto is the push down and twist type and stays in the ON position even though the pto only comes on for about a second and goes off
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There might be a relay in the fusebox for the PTO, probably best way to check it is to swap it with one from a known working tractor.
 
paddy farmer said:
good evening MF 30 I checked alternator today and its charging to over 14 volts. The switch for the pto is the push down and twist type and stays in the ON position even though the pto only comes on for about a second and goes off
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Does your pto speed come up on the dash? I had trouble with my ts115a. Same issue. Turns out it was the pto speed sensor coming from the pto stub. I used to turn on my pto but would stay registering 0 on the screen on the dash and then just turn off. I know with our old 7740 we had problems but I remember it being the yellow twist switch itself.
 
The wire to the solenoid goes in through the casing down the left side inside the diesel tank. There is a plug/connector at the top back corner of the diesel tank Infront of the axle. It is the smaller one that's there with just 2 wires where it connects into the loom.
You can just about reach it to disconnect it, depending on how long your arms are I suppose. Check for power coming here, should be constant power while the switch is on. Will tell you which direction your problem is. The plug itself was intermittently connecting on one of ours before.
 
Danielk said:
Does your pto speed come up on the dash? I had trouble with my ts115a. Same issue. Turns out it was the pto speed sensor coming from the pto stub. I used to turn on my pto but would stay registering 0 on the screen on the dash and then just turn off. I know with our old 7740 we had problems but I remember it being the yellow twist switch itself.
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Hi Danielk thank you for your response. Yes the pto speed comes up on dash even though pto is not working. I reved up tractor to 1900 revs and got a recording of 551 on pto. When pto switch is twisted to no position you can hear pto engaging but stops immediately
 
eddie86 said:
The wire to the solenoid goes in through the casing down the left side inside the diesel tank. There is a plug/connector at the top back corner of the diesel tank Infront of the axle. It is the smaller one that's there with just 2 wires where it connects into the loom.
You can just about reach it to disconnect it, depending on how long your arms are I suppose. Check for power coming here, should be constant power while the switch is on. Will tell you which direction your problem is. The plug itself was intermittently connecting on one of ours before.
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hi Eddie86 thank you for your post.We established that power is going to the solenoid . would you have any other suggestions ?
 
There's no pto speed sensor in the 40 series.The ECU or dash calculates a theoretical pto speed in relation to the engine revs.
From where the wires go through a rubber grommet into the transmission housing and on to the pto control valve/solenoid,it's a common issue for the insulation to break away completely from the wires,leaving them exposed whilst immersed in oil.
It's been quite a while since I had an 8240 with the same problem,but IIRC,I took off the wheel and was able to pull out the fuel tank enough to let me remove the round plate (after draining the oil down) and get my hand and arm in and feel the wires.The insulation had broken down, but I was able to remove the spade terminals on the solenoid,pull the wires back,cut off the terminals, push new wires through the grommet and crimp on new terminals and refit to the solenoid. All done by feel.May be easier to remove the lower fuel tank btw.
 
paddy farmer said:
hi Eddie86 thank you for your post.We established that power is going to the solenoid . would you have any other suggestions ?
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How have you confirmed power is going to solenoid?
If you have checked as I suggested, next step is what @agrimax posted above.
If you know there is constant power direct to the solenoid I'm guessing the solenoid itself is the problem.
 
power only going to solenoid for less than a second after turning pto switch on and sometimes no power or pto not turning on at all. as i mentioned on earlier post new switch fitted but acting same as old switch. Thanks
 
eddie86 said:
How have you confirmed power is going to solenoid?
If you have checked as I suggested, next step is what @agrimax posted above.
If you know there is constant power direct to the solenoid I'm guessing the solenoid itself is the problem.
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my brother is a motor mecanic and has a device to test power supply
 
Run power direct to the solenoid. That will tell you if it's the solenoid or not.
Did you check the wiring inside the fuel tank?
 
We're there buttons on the mudguards of those 40 series? Our 6080 would mess about with the pto every now and again but it tends to be sorted with a few presses of the mudguard buttons.
 
Our tm125 done the same pto came on and went out after a wile. Don’t know much about the different tractors but if you have solenoids for 4wd and diff lock like our 125 switch the solenoids over to see if that sorts it cured ours then we just replaced the bad solenoid. Hope this helps
 
Our 8240 had similar symptoms of turning off after starting it. Sometimes It could work for an hour and the go into a fit of cutting out, would drive Ya mad. Anyway turned out to the oil supply pipe had a hairline fracture going across the top of the back-end under the cab which was causing it. May not be your issue but just my two cents.
 
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