One problem related to frame rust has been reported for the 2000 Chevrolet Silverado. The most recently reported issues are listed below.
I was having the exhaust changed when I was notified that one of the cross members for the frame had rusted completely through and needed to be repaired. It has been repaired, but I was informed that excessive rust is in various locations on the rear of the frame and will need to be watched closely. Keep in mind that these cross members support the fuel tank and if one would break, it looks like it could cassette fuel tank to fall off. The truck has 100,500 miles on it, which is not excessive for the year. The truck spent most of its life in michigan, but now resides in illinois. I have read several forums having the same complaints for the 99-2007 model year vehicles. There are several holes placed on these cross members by the manufacturer that allow moisture in, with no place for the moisture to go once it is place. I am sure there is also a lack of proper paint application and even poor steel that is likely causing the issue. Just as Toyota has done, chevy should offer a recall for excessive rust on the frame. The Toyota tundra recall offers a new frame for any tundra with a rust hole 10mm or larger. Why isn't the NHTSA investigating this further? this a serious safety concern and also considerably lowers the value of the vehicle. Gm and chevy need to be held accountable for their decisions when designing and manufacturing these vehicles, just as Toyota took accountability for their decisions.