# New Holland T2420 EHSS slips out of gear



## Tflynn (May 16, 2018)

Hey guys, hoping someone can help me. New Holland T2420 Boomer with almost 700 hrs. This issue happens randomly, but it does happen every time I run the tractor. Basically what happens is while I'm going along the tractor just stops, as if someone has pushed the clutch in or thrown it into neutral. While stopped, if I push the clutch the tractor will lurch forward and stop again. If I let the clutch out, it will start to engage like normal then after rolling a couple feet the process starts over again. So far if I mess around with it enough (change gears, put it in reverse, shut the engine off etc.) I can get it to move again, but it's only a matter of time before it repeats. 

I had a similar issue at 500 hrs that was fixed with a new EHSS control box so I'm thinking (hoping) it's not that. I put on a new Forward-Neutral-Reverse switch yesterday which did nothing. I've tested the seat safety switch and even bypassed it and that's not my problem, I'm running out of ideas, can anyone help?


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## RC Wells (Dec 26, 2008)

Check the EHSS potentiometer down by the clutch fulcrum. I suspect it may have been the problem that led you to replace the control box. The symptoms of the potentiometer failing included erratic EHSS operation, shuttle going in neutral after the tractor warms from operation, and being able to get it going again after repeated foot clutch cycling.

It is a $150 part, and easy to check and to change if faulty.


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## Tflynn (May 16, 2018)

RC Wells said:


> Check the EHSS potentiometer down by the clutch fulcrum. I suspect it may have been the problem that led you to replace the control box. The symptoms of the potentiometer failing included erratic EHSS operation, shuttle going in neutral after the tractor warms from operation, and being able to get it going again after repeated foot clutch cycling.
> 
> It is a $150 part, and easy to check and to change if faulty.


Thank you that sounds like it could be it. I read your post and it got me thinking it does seem worse when it's hot. Is there a way to test it or is it something that you just have to replace and see?


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## RC Wells (Dec 26, 2008)

Your repair manual should list the test procedure.


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## Tflynn (May 16, 2018)

RC Wells said:


> Your repair manual should list the test procedure.


I don't have a repair manual but a quick Google search got many "how tos" on testing a Potentiometer. If I find one I particularly like I'll post a link for others that may encounter this problem. I'm just a little concerned that because this problem is intermittent that the potentiometer may pass the test even though it is in fact bad. I guess I'll worry about that if it does test ok. Thanks for the help RC Wells I think you're on the right track!


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## RC Wells (Dec 26, 2008)

Generally when one of these begin to fail you can run it through its range of motion a few times and an erratic change in impedance at the same point in the range of travel of a faulty one will be enough to know. But, not always, so if you have the specific OHM readings they should exhibit it will make the testing much easier as you are testing against a benchmark.

Perhaps the dealer service manager will give you the values you should see that are necessary to perform the test?


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## Tflynn (May 16, 2018)

I had a chance to test the potentiometer today. I couldn’t really find what I thought was a great instructional video, but I think I learned what I need to know. So as I understand it, you put your test probes on two of the terminals (just a very vague description) and it gives you a reading say 1700 ohms. Swing the arm on the potentiometer and the reading gradually goes down to zero, IF it’s working correctly. On mine, when I put the test probes on I get a 1700 reading...that gradually falls and falls all by itself (which would simulate pressing the clutch). If I would swing the arm down and back, the reading would fall to zero and back up to 1700 as it should...then begin to fall again. So in other words I’d say the Potentiometer failed wouldn’t you? Thanks for the help!!


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## RC Wells (Dec 26, 2008)

The reading shold be steady if the potentiometer is good.


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## Tflynn (May 16, 2018)

Ordered a new potentiometer from Messicks last night, will let you guys know if that fixes it.


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## Tflynn (May 16, 2018)

Update-

I finally got a chance to install the new potentiometer this morning and test the tractor for a few hours. I’m happy to say the tractor seems to be fixed! Thank you so much RC Wells! You nailed it


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## Hoodoo Valley (Nov 14, 2006)

Right on, I'm glad it was a cheap fix!


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## Guest (Sep 23, 2018)

Gotta like a happy ending!


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## romarid (2 mo ago)

RC Wells said:


> Check the EHSS potentiometer down by the clutch fulcrum. I suspect it may have been the problem that led you to replace the control box. The symptoms of the potentiometer failing included erratic EHSS operation, shuttle going in neutral after the tractor warms from operation, and being able to get it going again after repeated foot clutch cycling.
> 
> It is a $150 part, and easy to check and to change if faulty.


I have the same problem as you. The tractor gets out of gear, I press the clutch and the tractor goes a few feet and stops.
I change the potentiometer on the clutch and everything works for a while and the potentiometer breaks again. Is that the case with you?


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## romarid (2 mo ago)

romarid said:


> I have the same problem as you. The tractor gets out of gear, I press the clutch and the tractor goes a few feet and stops.
> I change the potentiometer on the clutch and everything works for a while and the potentiometer breaks again. Is that the case with you?


My tractor is new holland 8360


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## pogobill (Jan 31, 2012)

Welcome to the forum. This is a pretty old thread, with most respondents not returning for 2 years or more. You may want to ask the question in a post of your own.


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