Nothing that HURT the frame..that's for sure. But i did a CARFAX on it..and it's always been registered, bought, and driven down in Miami, FL until I brought it to tampa. IN florida... undercoating... is the biggest waste unless you are a "beach person".. ie jetskis, boats, live on the water and own your truck longer than 10yrs. My gramps' 68 Oldsmobile stationwagon was a FL vehicle..it's whole life and that sucker died with a Mint clean under carriage back in 88. So coating 99.99% of FL cars and trucks.. POINTLESS. I'm scrapping it off b/c A- It flakes off it you look at it wrong and B- EVERYONE can see the frame with a 3" body lift and my trucks looks DIrty..like i forgot to hose off the underside. should only take me about 2hrs to remove all the crap and give it a nice coat of semi-gloss black enamel from rust oleum.