i agree with redrkt on this one, when nothing is slipping it's 50/50 based on the video. the power is equally split coming out of the centre differential. but when let's say any one wheel slips, let's say the front left like in the video, then the open centre diff diverts to the front, then the front diff diverts to the left. if it was the rear left slipping, then it would be spinning that rear left wheel only while the other three wheels are not moving. if that was the case, you would lock the centre diff and you'd have both front wheels + rear left wheel spinning now. think of a fwd car, normally, the power is split 50/50 between left and right, but when you slip one wheel, the side that is slipping is the one that spins while the other is steady. LSD would fix that and turn both at the same time. if you think of the fwd diff as similar to the centre diff, the lock is similar to a fwd LSD in the way it locks both front/back. the lock doesn't "activate" the rear, but simply locks the front and back together in case either one slips. by your logic, if it was the rear slipping instead of the front, the car would be rwd and the lock would "activate" the front..