I would look at swapping in a complete e-locked rear axle. Inchworm sells the wiring you would need for it to engage.
http://www.inchwormgear.com/store/index.php?cPath=25_62

Here's one way to find your axle ratio:
http://www.getahelmet.com/jeeps/tech/findratio/


Wheeling a Stepside Tacoma on 37s
Exploring in a T4R Ltd V8