I have been fording rivers and going through creeks all summer without issue. I get my oil changed at Mobile-1 and have had them check the diffs and trans fluid regularly.
I don't know if what you are doing is more extreme, but I havent seen any problems yet. I do repack my Warn manual hubs every couple months due to high usage and river crossings.


2002 4dr Kia Sportage 4X4
Tires:235/75/15, Wheels: Black 15x8 Steel ProComp 2.5" B.S., Hubs:Warn Manual, Lift:3" UPYOURKIA, Trailer Hitch, Cargo Rack, Clinometer.