It appears to be a solenoid, IIRC that was used on a TH400 trans as a kickdown, not sure if it can be done away with, but I believe it would originally be attached to the pedal inside the car.
Its a switch that activates the kick down.
Google says i can remove it and down shift manually but... i dont want to shift this car so Im gonna look for the pedal mounted switch to clean up the engine wiring.
