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Discussion Starter · #1 ·
I picked up a 1978 2640 and the FEL was not working or the bucket after driving the tractor a short distance and stopped. I changed the hydraulic fluid and filter and cleaned the screen. The fluid was nasty, like green puss.
The screen had globs of like a gel on it but no metal particles or plastic pieces and cleaned up well.
After changing the fluid (HY GARD, approximately 7.5 gallons) and topping it off a couple times after running around the yard, the loader and bucket would seem to run fine while driving the tractor but when I would stop the loader/bucket would either not work or very slow or chatter a little. I drove around a while moving bucket and loader to try and get new fluid to all hydraulics and wash out the nasty stuff to see if it would get better. It really did not, when I would stop and move the loader and bucket might work okay a couple times or slow then not work. If I let out the clutch and started to move the loader and bucket would work again. The throttle rpm did not make any difference. I know these are good tractors but the hydraulics can be a pain. Any thoughts of where to start first? Thanks
 

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I'm not positive on this, but I can recall something similar. I think it had to do with a version of tractor with transmission PTO, and a two stage clutch. The transmission pump and PTO are both driven by one shaft that only spins when the clutch (PTO clutch) is engaged. With the clutch pedal fully depressed the shaft stops turning so the hydraulics are affected. On other tractors with independent PTO that shaft is live. Which type PTO does this tractor have? If you have a two stage clutch you might try experimenting by having the clutch engaged when using the hydraulics to see what difference it makes.
 

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Discussion Starter · #4 · (Edited)
Thanks Fedup and Tx Jim
From what I can tell it is a continuous-running PTO with only mid PTO lever only. It also has a reverser which per the manual shown in the image attached that it would be a single stage clutch. With that I am sure you are both onto something about clutch being engaged. I can not say I have confirmed the loader and bucket work better in neutral and clutch engaged. I only know everything, including power steering starts to work as soon as I leave out the clutch and start moving. I am better understanding the double pump situation (Low pressure Transmission pump feeding high pressure main pump) and maybe expecting too much repetitive movement of the loader without the clutch engaged.
I am sure the combination of two long loader cylinders and two bucket cylinders takes a lot of the stored fluid and may become starved if use in combination. I will have to see if I can try using again with that in mind and if I keep to minimal movements when clutch pressed in it may just be the nature of the beast. I don't know. I will have to do more investigating if it has a oil return modification kit which is supposed to help this. There is a hose connected to the bottom of the filter housing but not sure where it goes to or should go to. Also @@Tx Jim, I see you also responded in greentractortalk and I want to confirm the relief valve is not stuck? How do I check it, do i remove plug number 22 and the components will come out with the spring or do I have to remove the filter housing and try to see if it moves or both?
Any other insights would be appreciated. Thanks


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You're correct in removing cap(item 22) in parts diagram will give you access to hyd filter relief valve which is designed to not be stuck open in trans case. So I suppose your tractor has no lever with yellow knob located between the 2 gear shift levers?
 

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Discussion Starter · #6 ·
You're correct in removing cap(item 22) in parts diagram will give you access to hyd filter relief valve which is designed to not be stuck open in trans case. So I suppose your tractor has no lever with yellow knob located between the 2 gear shift levers?
Thanks I will try to pull out the valve and confirm not stuck open. Also that is correct, no knob between shift levers. I will also try to give you a better idea of the loader control valve (Which is mounted right on the 146 loader) and where the fluid is supplied from and returned to. I do know the selective control valve is not used, the hookups are independent under the tractor and maybe are at the pressure control valve. Since the SCV is not used, does the oil return modification kit mentioned relative to my situation and if so how would I confirm if I have or not?
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FEL control valve return oil should be attached to hyd oil ported filter cover. If FEL control valve happens to be the type that has a closed-center conversion plug then the inner seal on plug could have failed. We can address that issue when when you post photos of control valve the next time you visit tractor.
 

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Reverser tractors will definitely stop transmission pump if clutch pedal is pushed all the way down. During normal driving without using pto, you should be able to shift gears and stop tractor motion by pushing pedal half way down. If not, then clutch rod attached to pedal probably needs adjustment. Pedal should push half way down with pretty easy effort and then get harder to push. Try pushing down just far enough that you just feel the extra pressure and see if tractor motion stops and you can shift.
 

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Reverser tractors will definitely stop transmission pump if clutch pedal is pushed all the way down. During normal driving without using pto, you should be able to shift gears and stop tractor motion by pushing pedal half way down. If not, then clutch rod attached to pedal probably needs adjustment. Pedal should push half way down with pretty easy effort and then get harder to push. Try pushing down just far enough that you just feel the extra pressure and see if tractor motion stops and you can shift.
 

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I have a 67 John Deere 2020 with a FEL. The main hydraulic pump is mounted directly to the front of the engine. That pump has a round screen filter on the top of the pump. You might look and see if yours has one that might need cleaning.
 

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Discussion Starter · #11 ·
I have a 67 John Deere 2020 with a FEL. The main hydraulic pump is mounted directly to the front of the engine. That pump has a round screen filter on the top of the pump. You might look and see if yours has one that might need cleaning.
Thank you, I know there are some pumps with the screen but after looking at it and checking with JD, my model does not have one.
 

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Discussion Starter · #12 ·
Hello all,
I think I may have found the problem. Sometimes it is the simple things. At least it seems to be the fix.
When I purchased, the owners son said he topped off the hyd fluid and pulled the dipstick. He said to check it without engine running. Well, I got the owners manual and found it to say the fluid needs to be checked with the tractor running. I ended up adding 2.5 more gallons which would be a total of 10 gallons like the capacity chart showed.
Hopefully this will be the fix and will have many more years of trouble free hydraulic issues. From all of the forums I have read, it could be a nightmare. Thanks for all of the suggestions.
 
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