3 wires go to your selector. A hot one and then the other 2 go to the shift motor. If you have a push pull switch, up is high axle. If you have a shift knob, to the left is low axle. I don't remember if the terminals are marked. If not you will just have to do it by trial and error. If you have a speedo adapter, splice it into the low axle circuit. Originally the hot wire came from the ignition switch, I would recommend going through a relay because you probably have all you can handle through the ignition switch. There is nothing to interfere with your automatic, but I don't think you will be able to split shift. I think you will have to start in low axle, let the automatic shift into high and then shift the axle into high.
