[Axle]

My year round truck winter and summer. Get it oil sprayed in the fall. Wash it when I get around to it over the course of the winter, and a good thorough watering down underneath on the driveway come spring time. Spray any questionable spots, or spots that have broken through the paint with Fluid Film (yes, it'll leave the spot dark/black as it gets dirty but it works to slow down the rust. Its a driver not a show truck).
Does it stop the rust? No, just slows it down because the calcium chloride, the beatjuice/urine formulas they spray on bridges these days is aggressive.