4x4 actuator upgrade | The Truck Stop Jan 05, 2011The thermal actuator came first, when you engage 4WD there is a soft piece of plastic, maybe even wax that has to heat up before the actuator engages. The electric version came out in 98 or so and engages immediately. Myself, if I had that series of truck, I'd install a Posi-Lok and be done with it. Click here for the Posi-Lok.
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