Need someone knowledgeable on the ehydro system-4720!

[gcfisher75]

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!

 

[Silvic]

You do not state what the rpm was in B and C range. If low then that is not unexpected. C is mostly for "road" travel I would never consider it for doing any worthwhile work that had any torque requirement. More information as to the specifics of what you were doing and the rpm while doing it in each range would help a bit. Your description of pile would help for pile of straw, dirt, rock, gravel etc. All have different needs as to the approach.

 

[gcfisher75]

I'm sorry, I may make a video later if I'm able to, that might give you all a better idea... the top speeds were WOT (I think) no load just tractor and loader out a relatively flat driveway... for our purposes let's say it's perfectly flat.... when digging in the piles, I was on a dry gravel driveway... digging into frozen piles of snow that are left over from plowing the driveway... I would think that in "B" range a tractor of these specs should spin with maybe some effort even in those conditions... (York rake was on the back, and it has I believe a 5' bucket on the loader (it's just a tad narrower then the tractor)

 

[gcfisher75]

Even if rpm are low, when strained in any range, wouldn't the engine lug down and stall if you were to strain it far enough but pushing the pedal further? That is unless load match was engaged... (if I understand how it works correctly)

 

[beenthere]

My advice would be to get it to a dealer for a computer check. Then you may find out it is doing what it is supposed to be doing and just is "operator" challenge. Don't want to go adjusting things when not knowing what it is the computer is trying to do for you.

The idea of the e-hydro was to keep the operator from stalling out the engine by pushing harder on the hydro pedal. Sounds like you are fighting that feature, but admit I really don't know what the problem is you are experiencing. But e-hydro isn't the old mechanical..

 

[Silvic]

I have never lugged my engine down in B or C range. The tractor just stops moving or moves anemically when I have forgotten that I have it in B or C when I should not for the task I am doing. For that matter I have never had the engine really truly lug down with a 108" rear blade completely full of road material going up hill. Not like in the old days. It just gets a bit anemic and does not respond as well. The computer protects that engine quite well. I also rarely ever use full pedal except when I am roading the tractor. Just does not need it for the tasks I use it for, I need more control and slower responses.
With what you have said I would run it by the dealer and have them take a look at it. If nothing else it will give peace of mind.

By the way I have never had it at WOT. The highest rpm I use is the one for 540 PTO speed (2400rpm). What year? there have been some engine changes but not a lot and the ehydro has pretty much stayed the same.

 

[Dutch445]

quick thought,
is there any chance the park brake is on or the brakes are engaged?
if the tractor has sat for a while, and the park brake was on it may not
be releasing. i would think that the engine would bog down though, but,
A range would drive right thru the brakes.
your ground speeds are way off, A should reach 4.1 in F and R,
B should reach 7.2 and C range should top out at 16.9 per the spec page,
of course these speeds with the R1 tire but R4 should be relatively close.

 

[gcfisher75]

quick thought,
is there any chance the park brake is on or the brakes are engaged?
if the tractor has sat for a while, and the park brake was on it may not
be releasing. i would think that the engine would bog down though, but,
A range would drive right thru the brakes.
your ground speeds are way off, A should reach 4.1 in F and R,
B should reach 7.2 and C range should top out at 16.9 per the spec page,
of course these speeds with the R1 tire but R4 should be relatively close.

Ok, I got home from work and had more time to feel out the tractor and hopefully get a better description of whats happening...

Brakes are not the culprit, they work and release well. Without really knowing the tractor, to me it feels like the the tractor is not reading a full pedal travel with the go pedals.... It travels faster in reverse in all ranges then it does going forward it also has better reaction if you will when using reverse. all my speeds are off... on level black top road, in "A" range going forward i get 2.7 on r4 tires WOT (I'm only using WOT to give reference) with pedal fully depressed, In "B" range i max out at 4.4, and in "C" range 7.3.

Like i said tho reverse is faster in all ranges... i.e..in reverse in "C" range it will do 10.9, I didn't write down reverse in the other ranges but its roughly 2mph faster in reverse then forward... The pedals both feel like I'm getting full travel out of them, and doesn't feel like something is restricting their movement, it just doesn't seem like the computer is getting full input from the pedals, and obviously less with the forward then the reverse...

Dunno if any of this helps but this is what i have to give at this moment... I don't know the exact year of the tractor but it has the push knob for parking brake instead of the lever handle (i believe that means i have the older unit) I plan on taking the tractor to JD and having them give it a service and go over it and check out this problem if i can't resolve anything on here... thank you everyone for your input..

 

[Cocre]

Turn off LoadMatch. If that fixes the issue, calibrate the throttle position sensor.

At one point on my JD 3320 eHydro the tractor would barely move with LoadMatch on. Turning it off let it work fine, calibrating the TPS fixed the issue, but I generally leave the LoadMatch off all the time now anyway.

 

[Dutch445]

As Cocre said, there are calibrations that can be done on that hydro. I would bet the dealer can run your machine
thru the process and all will be good.