The reason you want 4lo gearing but not 4 wheels turning is to make it easier to turn, when you are backing up with a trailer you will at times turn the wheels all the way and it is a PITA if they are engaged, as well as hard on the front end. That is the biggest benefit to manual hubs. The only way I can think of is finding the right fuse to pull for the vacuum pump or some other thing in the systems that you can kill.