I have a really nice 3662 automatic milk car with the stand, and I am trying to figure out what's wrong with it. Let me get this out of the way first: the UCS track section is working, I rewired the controller, and tested it with the 3656 cattle car, which opened and closed perfectly and the little cows vibrated their way through the car just fine. On to the milk car....
The wiring insulation from both trucks are brittle, but the wires themselves look like they're fine. I opened up the piston and plunger inside the coil, and it was clean, as was the spring. On the track, when activated, there is a low buzz so I know there's some juice going to the coil. Moving the plunger by hand, the man moves and there is a much more audible sound as if it's working correctly. Do I rewire both trucks? Oil the moving parts at pivot points? I cleaned the metal surfaces lightly with steel wool. Any other suggestions would be greatly appreciated. Thanks and I look forward to the answer being found!