2840 hydraulic problem

This message is a reply to an archived post by squaredt on May 18, 2012 at 09:50:17.
The original subject was "2840 hydraulic problem".

I read your post about your John Deere 2840 having hydraulic problems. Where they will work fine, drive it around then all of a sudden there is no hydraulics, no power steering and the tractor looses speed. Then there is alot of noise from the transmission and it suddenly takes off again. I am having the exact same problems with my 2840 but am unable to find the problem. I was wondering if you ever did figure out what was wrong with yours?

Thanks

Have you serviced the screen and filters as per the operator's manual?
What kind of transmission oil?
The last time the front pump coupler and bushings were inspected and replaced if required?
Have you measured the transmission oil pressure at the test port yet?
There are transmission valves and lines that a plugged filter will damage with "water hammer".

Do hyd's fail with hyd hi-lo in both high & low? Do hyd's fail with pto on or off? How long since hyd filter was changed & sump screen(parts key 30) was checked/cleaned??

Hi
Thats exactly what the 1830 I was working on last winter did. I flow tested everything and flow would just disappear under load. The whole system on that tractor had filings in it from brakes and the rear end, pto bearings where loose in housings and all that good stuff. there are about 200 O rings in there sealing pipe fittings, and they start leaking with age to!. as well as circuit pipes wearing and fracturing.
I told this guy we could probably spend $5000 on the tractor, and it would be a gamble if it worked and for how long .
he decided to go buy a new better spec tractor and be done with this one at 17000 hours.
Those Deeres are a fantastic tractor when new but most are starting to show the same things with age and hours now, and are a complete pain to do anything with. our local dealer has nobody in the shop old enough to know about them now either. so they just throw parts on them and hope they get lucky with "YOUR" money!.
Regards Robert

These are reasons that I dread this model,,Darn it.. But the trans pump draws oil from the sump screen then sends it through the filter(at this point the filter relief valves needs to be in the normal "closed" position)then to the transmission lube pipe (at this point the transmission clearances should be close enough to "not need" more oil than given),then oil needs to go up into the shift cover(a stupid idea) and over come a pressure regulating valve (making sure there is proper pressure for the PTO, and the Hi/Low functions)and "then" if there is plenty of oil left over after all this the upper regulating valve opens and directs oil to feed the front pump..so any leakage up to that point will not allow the pressure regulating valve to send oil to the charge circuit. This is "one" of the reasons why you loose hydraulic pressure after the system warms up,, and why it comes back for a bit after you walk away from it for a while. On 2840's I have found that the transmission lube takes more, or too much more oil after time and wear, so I have been drilling and taping the transmission lube port to, I think 1/4" pipe thread and using a 1/4" Allen head pipe plug,drilling a 5'16" hole in it and using it as a orifice, this cuts back the flow being lost in the lube, but still gives enough lube to keep the transmission satisfied,,I have done this several times and it helped to send more supply oil to the front pump,,,but leakage in the other areas can still be a problem, it takes some time and patience to deal with them,,and I'm about to go into a 2955 with similar issues today...

IMHO 2840's were right behind 2010's as the 2nd sorriest tractors JD ever put their name on. I had failures on the brand new 2840's I sold. One of them required a new trans case under warranty.

I had a 2840 with hydraulic problems also, best thing I can say is get rid of it as soon as possible, nearest nothing tractor I have ever owned..