Similar issue here... the deicers are brutal. Much more corrosive than simple salt.
We had a 7.3 that ran well, thought we were going to keep it for a few more years. Was extremely clean inside, even with 250k. Had a small issue with the rear main seal after some tranny work. Answer was "I'm not touching it". Oil pan was paper thin from corrosion, and he continued that the driveshaft was thinning badly, and on and on. Frame actually didn't look bad, but over all, it was only a matter of time.
Had to re-think this problem.
Now, just about every time we return from sledding (lot's of winter driving, minus, cough cough, this year ( it really #*#&! sucked ) I drive the truck and trailer up a set of ramps. Turn on the sprinkler and go to bed.
Takes about 6 hrs to rinse off the underside of the two.



Thought for the day: common sense, should be.