Have the EX that when you lift the safety lever it will start moving forward. If you push the sticks up halfway it will stop. it will go forward and reverse but will not stay neutral without holding the sticks.
Are you saying that you have to hunt for neutral ? Do you have the straight line travel option? That would be the left pedal. Is it both sides with unwanted travel?
No when you engage the occupant safety lever it both tracks go full speed ahead, push both track sticks in the opposite way the EX is traveling and it will stop, push all the way and it will go in the other direction.
Does it have the far left pedal for straight line travel?
I believe it does but wasn't being used. I think it was locked out.
I would start by removing the pilot lines to the straight line travel pedal. That is the only place that will cause both motors to get oil in the same direction. Otherwise, off the two travel pedals you will only function left or right, the odds of both are near 0. Good luck and be careful.
I should clarify remove pilot "P" & "T" hoses. Cap them off, should just be regular orfs. That will take pilot control from the straight line. If oil escapes the open A or B ports of the straight line, then we have a shuttle valve issue, but at least we're narrowing the scope.