need part info

i need some help with the name of a part on my 1993 chevy siverado 3500. it is a 4x4. what is the true name of the part that is under the truck right next to the front dif. there is a slot for it and it screws right out. it takes a 1 and 1/4in wrench to un screw it and it has 2 wires running out of it. the slot that it goes in is forged right with the front dif. i think this is the part that engages the front dif.

realy need some help with that part name so i can go to a junkyard and get one.

front differential electric motor actuator