Why have the diff vent hose, line or tubing at the bottom of the vehicle where it can suck in water when playing submarine when cooling down the warm or hot diff when submerged in water?
Cooled down diff internal air space will contract hence suck in water.
The vent should be placed high as possible along with rear diff, transmission and transfer case up high in the body with a 180 degree short hook and filters attached....~~=o&o>......
The vent is as high as possible but terminates in a filter cap made of a gore tex material that keeps water out and oil in while slowly breathing to equalize pressure in the diff. There is a pretty good description by BByer on the Landroverforums website.