</font><font color="blue" class="small">( I will check on that, not sure this one has a mid PTO. But it is something to try. Thanks. Could it be a fuse maybe? )</font>
It can't hurt to check the fuses. Per the 4310 manual, I'd guess fuse F5 would be the most likely candidate, but you may as well check them all.
The online manual you looked at before describes how to change them and shows a schematic of the positions. Note the position F10 (Diagnostic) will be empty and if a fuse is installed, it will disable the tractor.
Just a thought...doesn't your rental agreement have an emergency contact number? Personally, I don't think it's a good idea to try to fix a rental machine. You could be liable for any damages or repairs required. Also, since the tractor didn't operate correctly, you might get some of your money back.