86 chevy c10 pickup transmission question
 

First thanks to anyone who replies to my little question.. I am not a mechanic and recently got into working on trucks. Well I have a 86 chevy c10 that I just bought and well it has a leak coming from the transmission. Well its coming from a electrical plug going to it on the drivers side. Trying to find out what this is called. Was told by previous owner that something bout that plug in was needing a gasket. What it is is a four pin plugin in and thats where i see the fluid leaking from. Its located on drivers side maybe center and above of the pan.
Its square and has 2 wires.