1) Switch inputs indicate shuttle lever is in both forward and neutral 2) Switch inputs indicate shuttle lever is in both reverse and neutral 3) Switch inputs indicate shuttle lever is in both forward and reverse. Cycle the shuttle lever which may free up stuck switches, or try driving the opposite direction.
One sign to move on is intensive UTB/Universal engine work, such as needing new pistons and injectors. If you hear loud clunking sounds from the engine, it could be due to the starter hitting the flywheel or a piston piercing the engine block, which can indicate a seized engine. Farmers encountering these problems have coined the saying: If your engine is knockin you better be shoppin.