Oil & Fuel JD 2640 with a few problems

[Rathpr]

I recently purchased a JD 2640 with 5,400 hours. I've never owned this tractor before and have afew questiosn if anyone can help:

1. The front end loader bucket is always slowly dropping and needs adjustment to bring it back up. It responds just fine but will start to drop again.

2. I unscrewed the cap for the transmission located above the pto and do not see any fluid. This seems like this is not normal

3. I need to get an operator's manual but need the tractor serial number to order from JD. I haven't been able to find it but have the engine serial number. Is there a way to find the right operator's manual based on the engine serial number?

This is my first tractor and would appreciate any help. Thanks.

 

[jenkinsph]

Depending on how fast the loader leaks down you may need repairs. How fast does it leak down?

Use the dipstick to check the levels for hydraulics, I have never seen standing fluid in the fill neck.

Where are you reading the engine serial number? Second is there no plate with model and serial number on your tractor?

 

[radman1]

I am not familiar with that particular model. The front end loader dropping could be due to leaky valve control. Are the hoses hooked directly into the rear SVCs or is there a dedicated FEL control valve. It could also be an internal leak in the loader cylinders but this tends to be less likely. It also depends how fast the FEL drops. Some drop is considered normal.

If you unscrew the transmission oil cap, it is very unlikely you would see any oil. If you saw oil, it would be way overfull. Look more carefully and you will probably find a dipstick. Some tractors have a sight glass but that was not common on the older, smaller tractors.

The serial number should be located on the right side of the frame.
TractorData.com John Deere 2640 tractor information

 

[Rathpr]

Thanks for the reply. The loader needs adjustment about every minute.I need to pick it up 6-inches. It has quick disconnect couplings for the loader. I dont see any fluid leak at all. Is this a problem with the the hydraulic pump?

I just came back from the shop and found the tractor serial number, it was under a front grill gaurd. The number was on the right front frame just above the wheel. I had to unbolt the front grill guard and remove it.

 

[radman1]

It is not the hydraulic pump. The pump does not hold the loader up. The valves hold the loader. If you have a separate loader valve, it is probably that valve. If you are using the internal hydraulics of the tractor, then it is probably that valve. Are you using the hydraulic levers on the the tractor to control the FEL or a separate stand alone loader valve? Internal valve will be $$ to repair. I would consider 6" of drop in 1 minute as excessive.

 

[jenkinsph]

I agree with Radman that 6 inches per minute is excessive. That said an easy way to figure out whether it is the valve (most likely) or the cylinders would be to put a small block under the loader bucket. Stop the tractor, wiggle the cylinder valve handle then unplug the hoses. Back off the block of wood leaving the loader raised slightly. Watch to see if it remains in place or leaks down. If it does leak down as before then the cylinders are the problem, if it stays up the valve is the problem.

 

[Rathpr]

Thanks for the help I'll give it a try. If you unplug the hoses from the valve that controls the motion of the FEL (with the two handles) wont you have fluid all over the place?

 

[jenkinsph]

Thanks for the help I'll give it a try. If you unplug the hoses from the valve that controls the motion of the FEL (with the two handles) wont you have fluid all over the place?

No, the ends seal off when unplugged. If the ends leak they need to be replaced too.

 

[TonyThompson]

Regarding checking the level of hydraulic fluid -- on my JD2640 there is a dipstick behind where your right heel sits. You should check it when the engine is idling. Take the dipstick out, wipe it off, and set it so that it rests on the threads.

 

[kennyd]

All good advice here so far excpet that the cylinders leaking internally (the fluid is bypassing the piston seals) is FAR more likely than a leaking valve. Since you have two cylinders in parallel, then it only takes one to be leaking for the symptoms you have to show. Finding which one is not necessary because you should rebuild them in pairs anyway.

 

[jenkinsph]

All good advice here so far excpet that the cylinders leaking internally (the fluid is bypassing the piston seals) is FAR more likely than a leaking valve. Since you have two cylinders in parallel, then it only takes one to be leaking for the symptoms you have to show. Finding which one is not necessary because you should rebuild them in pairs anyway.

Hard to know for sure which is more likely to be his problem not being able to see the tractor. Running the simple test I described would certainly help determine where to look next.

Not sure what you meant by the "which one is not necessary" comment as I was referring to whether it was a valve problem or cylinder problem. I agree that if the cylinders are leaking (either one) they should both be rebuilt in pairs.

 

[Rathpr]

Thanks everyone for the replies. I am going to do the test thsi weekend and see if the loader stays up with the loader valve disconnected. The other issue is also the curl. Not only is the loader dropping but is also rolling forward. Both are easily brought back into position but need constant adjustment. Is this more of an indication of a bad loader valve or cylinders or could it be either? Thanks again for all he advice.

 

[jenkinsph]

Test the curl cylinders the same way.

 

[kennyd]

Thanks everyone for the replies. I am going to do the test thsi weekend and see if the loader stays up with the loader valve disconnected. The other issue is also the curl. Not only is the loader dropping but is also rolling forward. Both are easily brought back into position but need constant adjustment. Is this more of an indication of a bad loader valve or cylinders or could it be either? Thanks again for all he advice.

The valve has two separate spool in it, so the problem does not point to the valve just because both functions leakdown. Do as Steve suggested and test both operations the same way.