JD Guru hyd pump 2640

NHbalerman · Jun 25, 2016

I am having trouble with my JD 2640 hyd they were real slow then they went out completely,found the transmission pump was broke (a gear was stripped) replaced it and it is working but the tank above the main pump is empty and I fill it up and the hydraulics work just fine until the main pump uses up the oil with steering 3 pt and remotes which does not take long,then nothing works also the pto is turning and it want shut off,I have checked every valve on it and the stroke control valve but I am not sure why the tank in the front does not fill up or the suction line to the pump is not supplying oil to the main pump or is it bad? Thanks

RogerinIowa · Jun 25, 2016

You are not getting any oil from the trans pump.

Tx Jim · Jun 25, 2016

If the trans pump is good,sump screen & hyd filter clean,hyd filter relief valve seating,hyd pto clutch and brake seals in good condition about only thing left is a high pressure leak in scv,steering,3pt or FEL valve if so equipped that keeps trans pump from being able to fill frt reservoir.

Have you diagnosed tractor for an internal high pressure leak??

Dave Sherburne, NY · Jun 25, 2016

I bought a 2640 in that condition once. The guy who split the tractor to work on it before me wasn't careful enough when he put it back together and he mashed some oil lines in the trans

Tx Jim · Jun 25, 2016

I forgot does your tractor have hyd hi-lo?

NHbalerman · Jun 25, 2016

The tractor does not have hi lo I cleaned the screen and changed fluid and hyd filter took the filter canister off and cranked it over and oil ran out fairly good took the top cover off where the shifters are at and cranked it and no oil came out of the tubes,the 2 tubes that go to pto are full of oil but the 2 big tubes are not,but is it possible that when I pushed the tractor back together from changing the trans pump could I have damaged the lines some how? This is not my first tractor split but you know we are getting old,but it seemed to go back together real easy

Tx Jim · Jun 25, 2016

With shift cover off hyd oil should exit one of the large tubes when engine is turned over. I think tube(parts key 4A or 4B) could be your problem but it's been many yrs since I viewed a JD utility tractor hyd oil schematic.

NHbalerman · Jun 25, 2016

Thanks TxJim I dont have any oil coming out of any of the 4 tubes in the picture with the cover off and the tractor running. I took the line off the main pump and off
from under the clutch housing and it had no pressure,oil did run out after I took the surge valve out or the ball and spring just to see if something might be stopped up.
I guess it is time to split it again and also I could see the shaft turning that turns the transmisssion pump but I might of got a bad pump although it looked good.
Thanks everyone for the help just keep it coming

JD Seller · Jun 25, 2016

I hate to say it but your going to have to re-split the tractor. You either cut an oring, crushed a tube/line, the transmission pump is sucking air, maybe the transmission pump is broken again. I had one that had a bad bearing behind the transmission pump that allowed the shaft to drift back and forth just a little bit. It broke a gear in the new pump I just installed.

Also did you remove the suction screen in the bottom of the rear end housing???? You could have other issues deeper in the transmission than just the broken charge pump gear.

Getting all the lines and orings together without damaging one can be a challenge on these tractors.

PS I just had a thought. Take the gear shift housing off again and blow air down through the two larger lines. See if you can hear a leak some where.

JD Guru hyd pump 2640

NHbalerman

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RogerinIowa

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Tx Jim

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Dave Sherburne, NY

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Tx Jim

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NHbalerman

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Tx Jim

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NHbalerman

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JD Seller

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