They really missed that one. Anytime you submerge your vehicle above the axle housings, you need to check for water. Water can actually be drawn in past the seals by vacuum from the warm housing being cooled quickly by being submerged in water. This goes for the transmission & transfer case also. Not to mention, if you’re in deep enough, they all have vents.
also on the landcruiser they have gearbox breathers at the top of the box,easy way to check if you have water in the oil is to pull the fill level bung and check the underside for white or creamy residue, if you get enough water in it froths up and forces out past the oil seals
It depends on how the axle, tranny, and Xfer case breathers are set up. On my jeep the breathers go through tubing to the top of the engine compartment. This way, no water is drawn in through the seals OR the breathers. The caller needs to find out if his vehicle is built this way or not. If not, then water could have gotten in.