Take it from me, cab swap time! I started getting rust in the windshield frame and A pillar on my original cab. I fought it and fought it until the firewall turned to swiss cheese and the cab mounts collapsed. Save yourself the headache and swap cabs. Rust down low in floors or rockers is easily cut out and replaced but rust up high is like Whack-A-Mole, you hit in one spot it's just going to show up in another.
