OK, there isn't supposed to be any such thing, so I am going to ask it I freely admit I am still learing about the 4wd drivetrain.

OK - you can't use 4wd on hard, dry surfaces since the front wheels can't slip independantly of each other, right?

So whats a front locker used for? Isn't it redundant? I've searched around, followed the excellent links to some of the beginner 4wd sites - but I am obviously not getting it...

Anyone care to draw the distinction for me?

Thanks!