Hey , I didnt know thats how 4x4 is engaged!
I thought you shift your gear down to D2 & move the other gear from 2x4 to 4x4 ; this gear is located in front or around the transmission.
Wow, thanks for the info !
By the way, I already figured out the "lowering-air pressure" part myself...! Makes total sense, whenever youre driving on loose mud or quicksand or some other type of soft soil/mud/ , lowering air pressure is smart!