You should use FluidFilm for the winter undercarriage protection, I have used it on my 4Runner and '90 Yota for 3 winters now, and you would never know it was daily driven in the salt. Spray it on in the fall before the first snow, it stays a liquid and deflects the salt, then pressure wash it off in the spring with degreaser. Downfall... It is derived from lanolin, so your truck will smell like a petting zoo for a while, and if you get it on the exhaust... Well it smells like burning sheep. I got the sprayer kit initially ($90), now I just buy 1 gallon ($50) every other year. I get four vehicle coatings out of 1 gallon. Want to meet up and compare undercarriages? Bet mine is cleaner! :rofl: