If you’re a 4th generation Toyota 4Runner owner, you may have heard of the phrase, “use it or lose it” being used. This term basically means that you should use your four-wheel drive system on a regular basis, otherwise it may stop working later down the road. The electronically-controlled 4WD actuator that is located inside of the transfer case can potentially seize up if not used for prolonged periods of time. Since the actuator is located inside of the transfer case, the transfer case itself needs to be opened before gaining access to the actuator. As you can conclude, if the 4WD actuator fails, you will end up with a costly repair. So “use it or lose it” to save yourself from future headaches.