We think we found the problem
We think it is operator error or more specific lack of operator training on how exactly the inching pedal works and when it is appropriate to use it.
Darrin took the tractor out by itself today so he could play with it and see if he could recreate the problems. As long as he operated the tractor properly he could not make it do what a couple different operators were having trouble with.
But then by doing some things specifically he should not do he was able to recreate the problems the operators complained of.
Specifically, in one instance one operator was having trouble when dumping grain into the truck from the grain buggy. He would hold the inching pedal down till needing to move forward. If the pedal is let come up just slightly, the switch clicks on telling the tractor it is in inching mode. Then as the operator continued to sit there waiting for the grain to pile up the tractor senses it is not moving when it should be and kicks itself in neutral. Just about the time the operator needed to move up so the truck runs over. Solution: operator needs to be in firs or second and use the gearshift to move forward and not hold the inching pedal down forever. Or if the inching pedal is held down, hold it all the way down so switch does not start engaging the transmission.
The other situation where the tractor was jumping to neutral while going through the field we believe the operator approaching the combine at high speed while downshifting would accidentally or intentionally touch the inching pedal. Darrin was able to get the tractor to kick itself in neutral by doing this. Solution: Operator keep away from inching pedal while operating the tractor - this is a powershift and not a manual clutch tractor. Inching pedal is for inching, not clutching.
We are not 100% sure yet, but pretty sure it was just the tractor protecting itself against operator error.
Always check the simple stuff first.
Oh, and the inching pedal calibration problem was simply that this tractor needed the pedal held down longer in the sequence of calibration than what the 765's need so once the timing of the sequence was correct it all worked.