I'm having trouble with my FLU419. I replaced the front wiring harness with an NOS harness. What a pain that was. Everything works fine now, or at least I thought it did. Everything works on the backhoe and the hydraulic tools. 4X4 and differential lock work fine. Since replacing the wiring harness months ago, I hadn't driven it on the highway at speed. I discovered that the intermediate speed control doesn't work now. It worked fine prior to replacing the wiring harness. It stays in low range regardless of where the collar on the shifter is located. Top speed is now ~25 MPH. The only electrical connections I see on the schematic is wiring to the panel light showing that low range is selected. Even though it is permanently in low range this light doesn't light. The bulb is new. I know the switch for the circuit is on top of the transmission and is closed or open as the piston moves back and forth between high and low range. I suspect that the piston isn't fully in the low range positon which would close the electrical switch and illuminate the light. I'm suspicious that the problem lies in the pneumatics, but it is also troubling that the problem developed when I replaced the wiring harness. I should also confirm that the pneumatic pressure is ~106 PSI. A while back, I rebuilt the top of the transmission with the pneumatic piston for the intermediate speed control. When I re-assembled the unit, the piston moved freely and had a new O-ring and was lubricated. It worked flawlessly after the rebuild, so I don't think that could be the problem. Does anyone have any ideas?