Excessive rot 2003

[pamoffa]

Hi guys, My last post was about how my brake line busted and I crashed into the car in front of me, I got all the brake lines replaced due to excessive rot. and was happy,, but the other day one of my leaf spring shackles gave way due to rot. My question is... just throwing it out there. What does Gm coat the bottom of these trucks with? or is it an option like rusty jones or something. The truck has only seen 6 maybe 7 winter seasons and what is confusing me is the exhaust is origonal and still in great shape. Isn't the exhaust usually the first to go? plus the body looks really good. I don't get it.