[molex]

Originally Posted by RockyMtnRay

This center differential is the key piece in "full-time" 4WD systems and all AWD systems.

Clearer now?

Yup, and "What about full-time 4wd's?" was my next question, thanks for answering before I even asked!

So what it all boils down to is: When all four wheels are getting torque from the engine and the truck turns on a dry road, all the wheels rotate at different speeds while turning. Because there is no "communication" between the front and rear differentials, they behave the way that they "think" is best, but because they don't know what the other one is doing, they work at odds to each other, and since the wheels can't slip or spin (like on a dirt road), stress builds up that could damage the drive-train.

Is that the gist? Anyhow, 4wd academics aside, don't drive in 4wd mode on a dry, paved road unless necessary.... which should be never. Got it.