John Deere 2640

This message is a reply to an archived post by JDseller on April 10, 2012 at 21:04:30.
The original subject was "Re: John Deere 2640".


We are having the same problem with our JD 2640. Hydrolics have slowly been getting worse for about a year now. We replaced both hydrolic pumps hoping that would solve the problem but it seems to have the same issues. If you rev it up the hydrolics will work a little bit. As the tractor gets warmer the problem gets worse. JDseller you had some great tips. We have checked your first and third suggestions so far. Working on the second one now. We would love some more advice if you have any other ideas. Thank you!!

Does tractor have hyd ind pto or hyd hi-lo? The supply tubes for both fore mentioned options have a history of leaking. Also with 3 pt raised,engine running look in hyd oil filler hole for spraying oil. Does tractor have a frt end loader with an ind hyd valve?

Neighbor's 2940 had leaking internal hydraulic lines caused by abrasion at the line mounting clamps. Split required to repair.

Dean

QUIT throwing money at the tractor and figure out the problem first!!!!!!

1) Drain all the hydraulic oil and remove the sump screen and see if it is full of junk. If it has lots of fiber looking stuff in it then the rear brakes are bad and they need repaired and then the whole tractor needs to have the hydraulics cleaned out if it was ran long this way. If the screen and oil look good then go to step two.

2) TX Jim had a good thing to look at that costs zero money. Start the tractor and raise the three point. Look through the filler cap toward the front of the tractor, for spraying hydraulic oil. The Mannheim tractors have plugs that are held in with snap rings, that cover where they machine the control vale bores. These plugs wiggle back and forth a little when the valves work. This wiggle eats up the orings on the plugs and then you have a high pressure internal leak. I bet that I have fixed a hundred of them.

3) Pull the gear shift housing off. ( Do not start the tractor with this off unless you like cleaning oil off the ceiling) Put it in park first and then just remove the bolts and lift it straight up. This will allow you to check the Independent PTO lines as they stick into the bottom of the gear shifter housing. The control valve is located between the gear shifters in the cover. These lines are a common thing to break. They vibrate and crack. When they do this the dump the charge/transmission pump oil right back to the sump and starve the main pump. Also look down into the housing and see if the charge pump lines are installed correctly.

4)When the tractor has been run long enough to warm the hydraulic oil up, Does the back side of the steering column feel hot to the touch??? I mean the casting about 6-8 inch under the steering wheel. This is where the steering control valves are at. They can cause the whole system to not work correctly. The real problem if you have an issue with the steering valve is that about 75% of the JD mechanics do not know how repair/rebuild these steering units correctly. Then to make it even better, since it an older tractor, most dealers will put the newest guy on it while the top mechanics work on the newer high dollar stuff. I know one guy that had $5000 dollars tied up in getting his steering valve to work correctly. This included buying several valves that had been rebuilt and where not good.

These are something to check. I do not remember the old post so listing the number of thing I said to do does not help me know what you have already done. Post use a short description of what you have checked so far. Also without two pressure gauges and a some fittings you really can't check the system out very much. These tractors have complicated hydraulic system that requires everything to work together or they will not work correctly.

I had a JD 2640 that I owned for 3 years. It had a loader on it before I got the tractor. The main hydraulic pump had gone bad. They just replaced the main pump. So the junk was still in all the rest of the system. In the first two years I had every single hydraulic component off and had to clean/repair it. Once I got everything working I shipped the tractor down the road. Once they have had a major hydraulic system failure they need to be completely cleaned out the first time so that nothing else is ruined. If they are run with the bad parts long the whole system is a problem after that.

Thanks for all the tips. We have drained the hydraulic oil and the screen was fairly clean so we don't think it is anything with the brakes. We looked inside the filler cap and didn't see anything spraying but will look more specifically towards the front. If the 3 pt is down and the bucket and steering are still not working correctly would that rule out a leak inside the filler cap? We will check under the gear shift housing and the steering coulmn too. Those are good ideas. Thanks.

(quoted from post at 07:28:10 04/12/13) If the 3 pt is down and the bucket and steering are still not working correctly would that rule out a leak inside the filler cap? We will check under the gear shift housing and the steering coulmn too. Those are good ideas. Thanks.

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If 3 pt is down RS can still leak and cause a problem BUT aren't as likely. I personally would only advise pulling the gearshift cover off as one of the last diagnostic steps. If tractor is equipped with both hyd ind pto & hyd reverser all 4 tubes can be PIA to get back into their holes correctly without causing a hyd leak. On checking the steering I'd disconnect supply line on RH side and cap it and use tractor a little while with just manual steering.

WHAT TYPE HYD VALVE CONTROLS THE LOADER????