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Need someone knowledgeable on the ehydro system-4720!

26K views 73 replies 20 participants last post by  Opister 
#1 ·
Just talked my dad into a new to him 4720 (700hrs) he has a new holland tc33 that this will replace and it took some doing to get him to go green...

We drove over 6 hours yesterday to get it, (got what I feel is a good deal) drove it there and tested it out, loaded everything up, paid the man and drove 6 hours back home...

Upon unloading at home and playing a little with it there it seems as if the transmission is not acting correctly... low range or "A" seems ok, no problem spinning.. however "B" range sometimes will bog the engine down, and others not so much, I think we got a high speed of 4mph out of "B" range forward and a little faster in reverse. Sometimes when going into a pile we could depress the forward pedal all the way and tractor would barely change tone.

"C" range is worse then "B" with more "slippage" if that's what u want to call it? It had a top speed of 8mph I believe and like 9.5 in reverse.*

It would do this with load match on or off, didn't seem to make a difference but im not exactly sure how load match acts normally because neither one of us have ever ran an e hydro, just mechanical ones... please help... I feel bad I talked him into this tractor and it's doing this. I think it's going to be something simple, I'm mechanically inclined and have a sense of some electronics, I'm thinking maybe it's a potentiometer? Can someone tell me how to test them and where they are? Could a dirty filter cause this? Thank you to all who respond!
 
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#2 ·
I would get that hydro fluid changed immediately. Even if it was acting ok, I would still change it so I know it is good. It could very well be the original.

Dave
 
#3 ·
I think I still have my service manual for mine, I think.....

I'll check for you tonight. It's for sale if I still have it.

-J.
 
#4 ·
Remember, the pedal is a speed control, not a power control. (I think that's why they invented the throttle:knownothing::lol:
 
#5 ·
Unless you have auto-throttle.....

I hope his solution is that easy, but I doubt it.....

-J.
 
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#8 ·
No I don't have throttle control, just load match, and right now with the way things are i can't tell a difference at all with that on or off.... Ive figured out through a post on another forum that my speeds are off... On level blacktop road, in "A" range, wide open throttle (just for consistency, no need to run the tractor wide open) and with pedal fully depressed im maxing out at 2.7mph according to the dash speedometer, In "B" range top speed is 4.4, and in "C" range it is 7.3... and in every range it is slightly faster in reverse I didn't write down "A" and "B" but in "C" range it'll do 10.9mph and the other 2 ranges are about 2mph faster then going forward... any ideas?
 
#14 ·
Your tires are on backwards....ba da dum:lol:

I can't help much with your problem but I did go through something similar when I bought my used tractor over the internet and a with a few phone calls. Long story short, it was a lonely sickening feeling that saturday morning when my transmission kept slipping out of gear as I watched the delivery truck drive away. I feel your pain.

Honestly I would call the guy you bought it from and ask him what the problem is or if there has been any work done to it. Maybe ask him what dealer he bought it from and call them to see what work they did to it. At least you would get some idea where to start.

I wouldn't get mad (even though you may feel like ripping his heart out through his face). The deal is already done and it will be a great tractor when you get it figured out. If you can control your emotions you might even get the seller to agree on a discount if there is something legitimately wrong and he knew about it and feels guilty.

It's also possible (benefit of the doubt, alot of doubt) that he did not know that it was supposed to go faster than it does and assumed there was nothing wrong.
 
#9 ·
I moved up to a 5M series.

I'm going to check for you right now.

All of your ranges are slow. From what I remember A max should be about 4, B about 6.5, C about 15 or 16.

Sumpin' aint right, but don't fret, you'll love the eHydro once you get her going.

Have you called the person who sold you this unit?

-J.
 
#10 ·
You, my Pennsylvanian-in-$hit-from-your-old-man friend, are in luck. I have the tech manual in my hands.

Make me an offer. I can get it in the mail for you in the next couple days.

-J.
 
#11 ·
Hiya,

After you make sure the brakes aren't dragging, I would check:

1) Fluid level
2) Air in system from a low level or partially plugged suction filter or mesh screen
3) Charge pump pressure out of adjustment
4) Directional relief valve for sticking
5) Potentiometers on the foot pedals and make sure they have full travel
6) and since loadmatch isn't working, the ground speed sensor.

You didn't mention any trouble codes, check the display for codes, those are very good at pointing to the subsystem with issues.

Tom
 
#25 · (Edited)
Didn't I go over this stuff already? You guys are ignoring me, it's like you've turned into my wife and kids.... :unknown:

Seriously, the above are the troubleshooting steps out of a field manual for Deere E-hydros when the user reports "slow or lazy" performance. They list the fluid/suction filters/screens first as it's good practice to do a change out as contaminated fluid will plug filters and cause all sorts of wacked issues. Fluid can look just fine on the dipstick and be reeking havoc on the components. Not only that, you have no idea what the former owner put in there, it could be hydraulic lift oil or 10w-40 motor oil.

Tom
 
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#12 ·
Is it possible that your brakes are sticking? If you shift into neutral, you should be able to freely move the machine by pushing. Also, if you set the parking brake firmly, put it in c range, , load match off ,throttle it up some, then try to move. It should go into relief in both forward and reverse, and emit a loud screech.
What year approximately is your machine?
 
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#15 ·
I would make sure the brakes are not stuck on by getting under the tractor and make sure the pedal is releasing the mechanism. Then I would turn off the load match and see if you get the same results.

When I got me 4310 the load match was foreign to me. I did not understand the need for it and still don't. I leave it off an use the power of the tractor and the stuff between my ears to run my tractor.
 
#16 ·
Oh, man... I really hope this isn't a big issue. I know this would keep me awake at night if this was me. Others have suggested exactly my thoughts.

Changing the fluids and filters is always a good practice but it'll run you about $300...

Below is a clip from my 4720 tech manual... it's very handy if you want to take something apart!

Text Font Line Document Paper


I think there are several good leads there. Some are very simple to remedy.

I hope this turns out to be an easy one... you'll love the machine when it's healthy!

Matt
 
#17 ·
Oh, man... I really hope this isn't a big issue. I know this would keep me awake at night if this was me. Others have suggested exactly my thoughts.

Changing the fluids and filters is always a good practice but it'll run you about $300...

Below is a clip from my 4720 tech manual... it's very handy if you want to take something apart!

View attachment 42676

I think there are several good leads there. Some are very simple to remedy.

I hope this turns out to be an easy one... you'll love the machine when it's healthy!

Matt
No chance of me seeing page 481 is there? Lol fluid level is ok, and the oil looks clean, I still am going to do filter changes when I get the chance...if the pump were going bad, I wouldn't have the speed differential between forward and reverse, right?
 
#19 ·
Just curious,

Exactly what is "LOAD MATCH" and what is it designed to accomplish? I have seen it mentioned several times in this thread and I understand this is on a larger tractor than I normally putter with but curiosity is building......

Thanks in Advance for the answers.
 
#20 ·
It's a setting where the computer on the tractor will slow you down, rather than letting the engine big down, when you apply a load.

-J.


Sent from my iPhone using Tapatalk
 
#21 ·
Your description of the problem leads me to believe that the sump screen filter or the charge filter is partially blocked.

If that is the case, you might see evidence of the hyd fluid being too warm if not hot. Check the hyd fluid and see if it smells like it's been heated or is slightly foamy.

If the filters are not allowing the pump to move all the fluid the system requires, you might notice performance related problems with the steering, the 3pt hitch and the front end loader - if you have a loader.

Sluggish, slower response; hesitation or jerkiness and surging, etc.

Let us know what you find out.

AKfish
 
#22 ·
Ok, I can do that, the sump screen is a cleanable reusable part correct? And it's in that elbow with the two bolts at the bottom of the transmission? Will I lose all hydraulic oil? And if ao about how many gallons? And can anyone tell me if "shell tellus 46" hydraulic oil will work for this tractor? I can get it relatively easy and cheap through my work....
 
#24 ·
Gcfisher75

No chance of me seeing page 481 is there? Lol fluid level is ok, and the oil looks clean, I still am going to do filter changes when I get the chance...if the pump were going bad, I wouldn't have the speed differential between forward and reverse, right?
It goes on for pages... I'd vote for checking AKfish's suggestion first . It will rule out that potential restriction.

I don't know the particulars of the forward vs. reverse hydraulic circuits to comment on why it works better one way than the other. It is a clue for sure. Tomorrow, when it isn't going on midnight, I'll look in the tech manual to see if they give a detailed schematic.

If you get to the point where you need to check the pump output pressure (pg 481...), myself or someone here definitely get you the info required.

Matt
 
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#26 · (Edited)
Ok tmmrw I'm hoping my dad can get the filters and oil and sometime this weekend I'll change them and the hydro oil... pretty self explanatory? Drain from plug take spin filter off, take elbow off, clean screen, put back together, put new spin on filter on, fill til full on dipstick, start, run for a little bit, work hydraulic sytems and recheck?

Is the power steering filter reusable or replacement part?
 
#27 ·
Hiya,

IIRC, the power steering filter is in-line and it's a sintered bronze element, somewhat like an old GM Rochester fuel filter from the 60's. I clean them by soaking in acetone and then flushing it reverse from installed oil flow direction with brake clean. There is a replace @ hour limit on them, I think every 2K hours you need a new one.

Tom
 
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#31 ·
Here's a little info for you to chew on. You can see in the eHydro hydraulic schematic that the component marked "X" is the inline pressure side filter that ultimately comes from the power steering pump. It supplies charge pressure for the eHydro, as well as pilot pressure to the directional servo valves "S" and "R" which controls the stroke of the Ehydro piston pump "T". If that pressure was low, the pump would not go to full stroke.
The bottom line is...make sure that filter gets serviced.

I'm also including a little info on the basic theory of operation of the tranny.
 

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#32 ·
The plan is to do oil and filter changes tmmrw, I got the filters and oil today... I'm having a problem finding this inline filter, I understand where the sump screen is, and the spin on filter is pretty obvious, and I was under the impression the inline was on the drivers side just in front of the cab at or near frame level...
 
#37 ·
Ok, found the inline filter, and cleaned it, the sump screen, and changed the spin on filter, and added new hydraulic oil.... the inline and sump screen had some fine shavings and dirt matter but nothing that i would say is out of the ordinary especially if its never been done... oil looked used but not terrible. Doing the service didn't change the performance of the travel of the tractor at all, but we can now rule that out, so i guess onto the next thing... lol
 
#38 ·
Take a look at your manual,and make sure SpeedMatch isn't set. I'm not sure what options that you have installed, so you will just have to see what switches have been installed.

Also, take a look at post 12 that I posted a couple days ago. It's kind of a poor mans test of the eHydro pressure. I just want to see if it can develop enough pressure to crack open the relief.
 
#42 · (Edited)
I assume you had LoadMatch off during this test? Did you have the engine wide open?
The err 6 is just that the machine should be moving, but no movement is detected.


Unfortunately, I think you need to start checking pressures. Charge pressure would be high on my list.

What other symptoms are you having besides low travel speed? Does the steering work normally?

I'm attaching the diagnostic mode information. You can make sure the pedal sensors are reading in properly and you can verify you are getting a 100% PWM signal to the servo valves.

You could also try the calibration procedure.

I'm not sure how comfortable you are with working on it.
It may be time to take it to the dealer if you are in a hurry.
 

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#43 ·
First off, Thank you sooo much for the help so far, truly appreciated! The steering seems to work normally as far as i can tell (there is a small very minute amount of surging that is detectible sometimes, but its so minor i think it could just be the nature of the tractor... loader hydraulics are what i expect from the machine, all that I've had on the 3pt is an 8' landscape rake that the tractor came with... the only thing that i can come up with as far as something "wrong" with the tractor is load match doesn't change a thing as far as the tractor acts... on or off the engine bogs the same amount which is about none, it just quits moving if you try to go up a hill steep enough or overload it with the brakes/or loader work.
 
#44 · (Edited)
As far as being comfortable with working on it, Im pretty mechanically inclined... These are just a new species for me, and i don't know how it all works and where to look, but I'm learning! :) Not in a huge hurry, but we haven't told mom yet that dads new tractor is broke so the sooner the better! i can acquire a gauge and hose and fittings, and perform some pressure checks...

Is calibration hard? i read somewhere how you can mess things up and that kind of intimidated me....
 
#55 ·
Not in a huge hurry, but we haven't told mom yet that dads new tractor is broke so the sooner the better! QUOTE]


How is your dad holding up so far? You are certainly being as helpful as possible and trying to solve the issue for you and your father.

As is often the case on this forum, you have got some great members who are really trying hard to help you find the answers. Those providing pictures and manual sources, etc., in addition to the practical experience and suggestions is an example of how I have found this forum's members to be heads and shoulders above the rest.....Plus they stick with you and respond on a timely basis.

I noticed in the early postings where there were suggestions you contact the guy you purchased the tractor from and inquire if he was aware of any of these problems. I didn't see if you had any luck or response from him or if you tried. Just curious of his position on this, if any.

Hope you resolve this soon. Best of luck.:empathy:
 
#47 ·
Mine was a 2005 and the diag switch was left of the steering wheel.

Forgive me if this has been suggested, but do you have cruise?? There is a max speed setting on the cruise. Make sure that's right off, maybe even disconnect it???


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#49 ·
let me run an idea past you guys... I understand that somehow through the computer i can tell what value the computer is getting from the pedals, however i'm having a hard time figuring that out... is it a possibility to switch plugs on the pedals in a way that the forward pedal would become reverse, and vice versa? then if my forward speed was faster then my reverse it would have to be in the potentiometers or the calibration... correct?
 
#51 ·
yes you can switch them.
the part that bugs me is that the tractor stalls; It's not just a speed issue. And it bugs me that you can't develop relief pressure on the Hydro tranny.
In my opinion that rules out speed match and all that stuff. I wouldn't rule out loadmatch problems though.
Just make sure Loadmatch is actually shutting off.

I'll mess around with mine tomorrow and see if I can make sense of the diagnostic mode.
 
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