25 HST 4wd front right tire locked up in cold weather

[BCLoco]

I hope this helps someone out. I've included a pic of my tractor that I bought new in 2014. It has 188 hours on the engine and has always been serviced by the place where I bought it from. Last service was at 150hours. It has always slept outside but that may change next winter.
Tools needed:
-9mm open end wrench
-14mm open end wrench
-Something low to the ground to drain oil into. Typical drain pans found at auto parts stores are to high
-Rag to check the oil level once done
-Channel locks to get the yellow dipstick off incase someone put it on to tight.

Well done on getting the immediate problem out of the way. As for the water intrusion, do you see any oil staining around any of the pivot points or gaskets on that front axle? That's usually a dead giveaway of where the problem is. If not, be suspicious of the fill cap allowing water in. Since it's supposed to be well above the oil level, it can be the source of water intrusion without giving any signs.

The best thing for checking this is a smoke machine, but you can also do it with just compressed air and soapy water if you have a pressure regulator that can really dial down the pressure. Like less than 5 psi (3 is safer) or you risk causing yourself a leak. If you slightly pressurize the front axle, and spritz the gaskets and seals with soapy water, you should get some obvious bubbles.