The # 6 terminal is the power in spot for the operating solenoid. Here is a link to a basic and general diagram for the Borg Warner electric overdrive.
https://fifthaveinternetgarage.blogs...ve-wiring.html
The #4 terminal is for the momentary drop out when the kick down switch is activated. The solenoid also has internal points to provide the function for the solenoid. It's easy to remove the cover and have a look at things. The solenoid has a pull in coil and a holding coil in its make up. It takes more current to pull the solenoid into overdrive and a lesser about for the holding coil to keep it engaged so that the current needs are reduced for normal operation. I've purchased good units off of flea-pay that just need a cleaning. In the OP's case, the 12-volt solenoid would be the one to look for. Most of the car manufacturers that used the electric OD used the same basic solenoid but there were special ones made for certain applications.