I have a 2006 JD310sg, I was pushing some dirt and it quit moving, in forward or reverse. After fiddling around with the controls it started moving, thankfully because I was in the middle of the road. I drove it off the road and it quit moving again and has not moved since. I shut it down to put tranny fluid in it and found out it was at a perfect level. I went to restart it and it would not turn over. I have checked what I know with no luck. At this point I am thinking the machine is not recognizing forward, reverse or neutral. The fuses are good, the solenoid by the fuses clicks, but I do not know what to do. I have a mechanic coming in two weeks but I have to complete this road project asap. If you have any info to share I sure would appreciate it.
Welcome to HEF, Edward ! A serial number is need to get accurate help. The battery may be your problem have you checked it for voltage, and the cable connections ?
I don't know much about your model, but I bet it's electrical. Without a wiring diagram, start with Tinkerer's suggestions, then go to the key switch, then try to find the run and start solenoids, usually under the right "armrest" controls. A power probe is worth the money if you're not comfortable with a multimeter, like back of your hand familiar, use it with your eyes closed comfortable.
As said above, check the battery charge and connections. If you get it started, check the charge rate of the alternator.