The flange transfers the power from the turning axle to the wheel hub. On a part time four wheel drive they are usually unlockable, but an AWD needs to have all four hubs locked all of the time as the power will be transfered to the wheel that turns easiest when the difs are unlocked. When you remove one it will allow that wheel to turn at slower or faster speeds than the driven wheel, giving you much easier turning.
If your locker decided to unlock while you have a drive plate off, you would not go anywhere until you reinstalled it.
If your locker decided to unlock while you have a drive plate off, you would not go anywhere until you reinstalled it.