2004 750c #940376 wants to mistrack to the right forward and backwards, the faster you go the worse it gets. A JD tech tried new speed sensors and calibrating multiple times didn’t fix it. All wiring checks out good also. The machine does not throw any codes and will not complete or do the calibration correctly. Right now the tech is coming back with a transmission control box to see if it’s not calibrating because the box is bad and if that doesn’t work wants to bring it to shop to for more tests. Any ideas or past experiences would be great. Thanks I’m advance.
If it fails calibration there should be calibration codes (letters, numbers or a combination of both, 12357, A,D,d,E, L and r). If it mistracks that bad there should be codes. You might have to run it longer during the mistrack for the code to pop up. Even without codes you can figure out what the issue is just from the calibration failure. At what specific point in the calibration does it fail (what is on the display at the moment of failure)? What specific step during calibration is it failing? After lever movement ? Just after thresholds? After high speed calibration? Knowing where in the calibration it fails will tell you what is most likely causing it (even without a code). With a mistrack I wonder if it is the thresholds that are failing (27Lr in the display).
What the tech guy told me was when he starts the calibration both tracks move instead of just the one and when doing the left side it won’t blink off before the fnr should pop up. He said it like the control box isn’t recognizing the left sensor ever with new sensor and all wiring look and check out fine. That’s what I know. He is gonna find a different box and try that to see if that’s the problem next so until he comes back just asking if anyone seen similar issues with mistracking to the right with no codes and gets worse the faster you go and what their solution / fix was.
Update- the Tech tried a new control box that changed nothing, so Deere had tech check a couple more things and they told me they found there was no speed ring(it is broke or missing), does this happen or make sense? The previous owner will not return calls to give me any prior history of maintence to see if it was worked on and put together wrong.
Yeah, from the parts book the pumps and motors look like Danfoss, and they do use a pressed on pickup ring. I suppose anything can happen, with or without human intervention. There is an early and late speed sensor shown, and an early and late motor, don't know what the difference is. Your machine should have the late or newer parts. Possible early and late motors got swapped and the sensor is mismatched? Gotta think outside the box sometimes.
Yep, unfortunately he should have caught that much earlier in the diagnostic process. The 4th step in the mistrack flow chart says to check the speed ring.