I have a 2004 John Deere 750c dozer. It started having issues with the hydrostat. While moving, it will stop completely. Engine is fine and pressure gauge is fine. It will not let you cycle up in gears, only down and it will allow a very minimal amount of reverse movement. We changed the fluid, the filters and have attempted to get a code, but cannot get it to the diagnostic mode.
Welcome to HEF ljfanning ! A complete machine serial number would help. When you say it won't let you cycle up in gears, be more specific if you can. That machine does not have "gears" being it is hydrostatic. Is the speed control not working? Check your messages. Then post codes if any.
Thank you for your response, and it will not allow cycling up in speeds is correct. Serial number is 3-71094-4 Code that it showed was F645 Thanks again.
Have run into this several times wont speed up but will speed down. Pump speed sensor or connector. If you replace the speed sensor, try operating unit before going into calibration if works leave it as is. If unit has many hours and you go into calibration you may end up replacing many electrical parts to make it finish calibration.
Here is the Correct serial number T0750CX926679 To access that sensor, does the cab need to be flipped?
Yep. It is mounted on the left side of the front hydrostatic pump. If you replace that sensor, proper adjustment is turn it in by hand until it just touches, then back out 1/2 turn. For $370, I would first make sure the wiring is good.