Paint on the undercarriage (frame, suspension, rearend ect...) usually starts to chip/peel off after a few years. It doesn't look to pretty then. I know there are coatings like POR-15 but if there a way to seal the factory paint that is under there? Maybe something like a clear coat that would repell salt and sand. It could be sprayed on while the truck is new.

Good idea?

You could have somebody who does bedliners spray under there. I've seen that before.

My frame is coated with that greasy waxy stuff they put on. I don't think coatings would stick to it. I've already scratched a lot of it from running over bushes hunting.

BMGHauler's right, its a waxy coating that can't be applied or patched cold; your frame's actully dipped in it at the factory.

Your best option to protect it is a covering like fluidfilm. I've never used it personally, but I hear nothing but amazing reviews about it. I think it's sold at john deere dealers.

If you've already started to scratch it off, you can patch it with spray on undercoating for temporary...