Go BottomJohn Deere JD 4720 transmission problem
 | jbincconst
Join Date: Jul 2007 Posts: 3 Moore, OK 
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2007-07-18 143831
Anyone have trouble with E-Hydro pulling a fully loaded box blade. I bought the tractor 6-7-07 new, the problem is after the blade is full the transmission stops pulling, I have to depress the pedal almost to the floor to get moving again and when the blade unloads it lurches forward at a much higher speed. I can set the cruse at 1.5 MPH and load the blade and trans works fine. The dealer adjusted the trans and it works much better now but still could use improvment, the dealer said he could not adjust outside spec. Anyone have any ideas. JB
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 | kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon 
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2007-07-18 143835
What range are you in? Does the 4720 have a switch for LoadMatch and, if so, is it enabled? ....
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 | Billy
Join Date: Oct 1999 Posts: 975 Southeast Oklahoma 
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2007-07-18 143838
JB
Ken hit on what might be the problem. What range are you in? ....
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| jbincconst
Join Date: Jul 2007 Posts: 3 Moore, OK
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2007-07-23 143966
Loadmatch is off, I have to continually adjust foot pedal to get the tractor to move. The 4700 JD I own will climb a tree if I press the pedal down at 1.5 MPH in B range. I know the 4700 is mechanical Hydro and the 4720 is E-Hydro but I expected more with 10 more HP. JB ....
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 | earthwrks
Join Date: Dec 2003 Posts: 3853 Home Office in Flat Rock, Michigan
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2007-07-23 143976
I'm not a JD guy but I think I read somehwere something about an electronic switch or potentiometer that reads where the pedal is. I've heard they can go bad or get wet and short out . ....
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| pelletfarmer
Join Date: Aug 2007 Posts: 14 Central Michigan
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2007-08-21 144889
I'm just a rookie--got my 4320 in the spring too--but I don't think you wanna mash on the pedal there. Since it's not a throttle, you're just asking for a higher gear when you want a lower one, or something like that. Me, I don't use cruise. Some guys swear by the load-match and leave it on all the time; I don't. But then, I don't have a box scraper yet because nobody in mid-Mich seems to have an old one lying around (hint, hint).
What rpm are you running? What happens in low range?
....
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| jbincconst
Join Date: Jul 2007 Posts: 3 Moore, OK
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2007-08-27 145104
I run the rpm 2000 to 2400, the trans seems to pull better in low range. The trans problem seems to be worse after it heats up. The dealer came out and I demo the problem, they said run at higher rpm. The trans is much better now after the dealer adjusted the electronics, however on occasion the trans will stop pulling and the engine is not loaded.I have other problems I am trying to get fixed, leak down and the radio does not work 1/2 the time. ....
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| pelletfarmer
Join Date: Aug 2007 Posts: 14 Central Michigan
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2007-09-03 145311
Sorry, I missed that post. Doesn't sound good at all...I hope they got more than "run at higher rpm"! Reading back about the cruise and now your mention of radio, sure sounds like something funny electrically. Leak too, eh? "On occasion the trans will stop pulling" with no load...whew.
Did all this start just with the full boxblade, or were there problems earlier? Whatever the problem is (are?), I hope you get an actual fix. Thanks for letting us know. jk ....
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2007-09-04 145331
I am NOT a Deere expert at all, but I do know from speaking with a friend who has one that the dealers mechanic told him that JD has 'tweaked' some of the programming to 'fix' warranty problems they were having that were borderline abuse, not mechanical failures per se.
Amongst those mentioned was lugging a hydro, this is a killer on those machines. With an E-hydro I could see where it would be really easy to just tell the unit not to overload itself at RPM's that were too low for the power demand.
A comment like "...after the blade is full the transmission stops pulling...". a FULL box blade is a huge load, in fact probably about the biggest load that the average 3pth will ever see.
Maybe somebody else has run into this.
Best of luck. ....
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| jbarrett
Join Date: Jan 2004 Posts: 5 oklahoma
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2007-09-06 145447
In my opinion the electronics is the problem, if this is the same trans as the 4700 it should be pretty tuff.I have put 1200 hrs. on the 4700 with same box blade, B range. I really never had a major problem except creeping. The 4720 does OK until it gets pretty warm then I have to go to low range which is ok but why I've got 10 more HP to pull through the tuff spots. I put the cruise on it works fine, JD just needs to get it's act together, should be no reason the 4720 will work in B range. JB ....
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| Billy
Join Date: Oct 1999 Posts: 975 Southeast Oklahoma
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2007-09-06 145453
You don't say how many hours is on the tractor. Has the transmission suction screen been cleaned and the filters changed? ....
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| Lwayne
Join Date: Sep 2007 Posts: 95
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2007-09-13 145689
JB: This is my first post on this forum but your 4720 problem caught my eye. I, too, have a 4720 (with an 84" box blade). Recently I've been grading a 27,000+ sq. ft. parking lot with clay and gravel. I use the Loadmatch religiously and the unit seems to operate as intended, though a full load of either clay or gravel is the most I'd want out of her. I operate in the first range, usually around 1500 rpm's. If you have a 96" box, that might be too much. I don't know. Your problems sound kind of scary . . . sure hope you got to the bottom of it. ....
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