Is MDU of an OnTrac2 repairable? I purchased an Edge display to put in a combine and the guy also has a OnTrac2 system to go with it. However, the MDU motor is bad. The local dealer didn't have much knowledge about this system. just wanted to sell new. Can they be tested/repaired? Average repair cost? Reman units available? Just need to know what my options are before I buy the steering system to put in a tillage tractor.