I cant recall any diff on my vehicles I opened up looking any different,they all had milky gear lube and some rust on the parts that dont contact each other..
I never had one give any grief after a good flush and new lube,even one that looked really nasty inside...I doubt any of them ever had a fluid change,and all had well over 100K on them..
One advantage to frigid weather is the water will freeze and ice is easier to remove than water is...once I needed to add some tranny fluid to our torch car at the junkyard,all we had lying around was a pan of dextron we drained from a transmission,that had about a quart of water in it...
I put it outside ,it was about 20 degrees out...about an hour later,I was able to pour the dextron in without any water in it,all the water was frozen into ice!..