M125x won't shift above 4th gear

[Kkingsfield]

The tractor runs fine in high or low as long as it's in 4th gear or lower. When I press the upshift it will click briefly to 5th then revert back to 4th gear. If I press it multiple times it will go all the way to 8th gear but the machine won't move. Shift back down to 4th or lower and it runs fine. I'm praying that it's electronic. Shift Solinoid? Relay of some kind? Suggestions?

 

[NorthwoodsLife]

Look online for M125x transmission "Recalibration".

 

[North Idaho Wolfman]

The tractor runs fine in high or low as long as it's in 4th gear or lower. When I press the upshift it will click briefly to 5th then revert back to 4th gear. If I press it multiple times it will go all the way to 8th gear but the machine won't move. Shift back down to 4th or lower and it runs fine. I'm praying that it's electronic. Shift Solinoid? Relay of some kind? Suggestions?

Get the WSM (aka service manual) it should explain how to test and calibrate it.

 

[Fedup]

So both you guys think this a just a calibration issue? I'm not saying you're wrong, just that I don't see it that way. From what I can tell this transmission is (in some ways) similar to the 16 X 16 transmission Ford used in some of their early powershift forty series tractors. Four speeds in low range and the same four speeds over again in high range.

What I read in the problem description is that all is well in low range (tractor operates in one through four) but when the demand comes to shift from four to five the system should then drop the low range clutch, pick up the high range clutch, go back to gear one, and thus be in gear five. This isn't happening for some reason. The low to high shift isn't taking place. Is that a calibration issue? Not in my mind. In my understanding calibration (basically) adjusts the speed at which clutch packs engage and disengage based on factors of engine speed, ground speed, gear selection and whatever other parameters the engineers chose to include. Maybe someone can help me understand how that's what this problem is.

 

[NorthwoodsLife]

Strange...
Kubota M125X Issue, Need help | OrangeTractorTalks - Everything Kubota

 

[whitetiger]

So both you guys think this a just a calibration issue? I'm not saying you're wrong, just that I don't see it that way. From what I can tell this transmission is (in some ways) similar to the 16 X 16 transmission Ford used in some of their early powershift forty series tractors. Four speeds in low range and the same four speeds over again in high range.

What I read in the problem description is that all is well in low range (tractor operates in one through four) but when the demand comes to shift from four to five the system should then drop the low range clutch, pick up the high range clutch, go back to gear one, and thus be in gear five. This isn't happening for some reason. The low to high shift isn't taking place. Is that a calibration issue? Not in my mind. In my understanding calibration (basically) adjusts the speed at which clutch packs engage and disengage based on factors of engine speed, ground speed, gear selection and whatever other parameters the engineers chose to include. Maybe someone can help me understand how that's what this problem is.

OK, so don't recalibrate it.
It is significantly different the the NH 40 series powershift transmission, I am very familiar with them also.

 

[Fedup]

I take it you agree that it's still a calibration issue? That's the solution here? Maybe you're right. I'm not saying calibration wouldn't be in order once the problem is solved, I just don't believe calibration will solve it.

I hope we find out some day.

 

[whitetiger]

I did not say that will solve the issue, it is the starting point though, simple things first.
Sometimes it will solve the issue.