Sounds like a personal problem to me. You may want to see a doctor and get that checked out! I would HATE to have water in my rear end!
The 2 most common causes are from either excessive condensation, which usually means you have vent problems, or from driving through deep water, and you definitely have vent or worse problems.
I had water get in mine from a vent leaking. Lets just say I had to buy a new 3rd member because it wasn't caught fast enough. $3800 mistake lets just say there was huge chunks of metal in the oil and they almost didn't accept my core.
YES!!! Had the same wheel-end seal go out 4 times over a 3-week period, always had water in the fluid. Had the local Mack dealer doing the work, and they seemed confused since I denied driving thru deep water every 4 days. Replacing the vent didn't help. At least I only paid for the first repair. Finally someone in the shop decided the rears needed to be re-sealed since every time I worked on a rainy day the seal blew. Didn't know there was such a procedure; big labor charges, but very little parts since they used what appeared to be white silicone sealant along the horizontal surfaces of the rear halves. But at last the problem was solved! May be your problem as well...
