We have a BT Prime Mover RRX35 that will not travel. It is showing no code and makes every indication that every thing is OK. Battery is in good charge and all of the switches have been checked and are working correctly( dead man, driver present,....) all other systems are working, steering, all hydraulics. the drive motor has been checked and the break is working correctly also. We do not have a manual for this model or a schematic. Any suggestions would be of great help.