There’s more: Your differential probably has a vent. If you get your axles good and hot and then shock-cool them driving through a cold puddle, the air inside

There’s more: Your differential probably has a vent. If you get your axles good and hot and then shock-cool them driving through a cold puddle, the air inside the diff may shrink and suck water in through the vent. Gear oil plus water equals a substance which will not lubricate your differential gear and unless you drain out the foamy oil/water soup, you’ll have Problems.