DCP, I'm having the same problem with my Silverado, and share your frustration with GM. I bought my truck new last August, in March my truck had just over 4000 miles on when I noticed a black piece laying on my garage floor, it turned out to be the undercoating from my truck's frame. The more I looked the worse it got. The undercoating was peeling off the outside and inside side the frame in 3-4" size pieces exposing bare metal. In some of the boxed cross members there was loose pieces of coat pealing off and laying in the bottom of the frame.
I called the dealership, they told me a batch of frames went to undercoating before being painted, but GM has a fix for the problem. I was wasn't born yesterday and know it will be impossible duplicate factory applied coating at the local dealership. I said GM can have this truck back, but the dealership went quite after that and did not hear from them for weeks, till I called again. Frustrating when this was the 5th new GM product I bought through them in the last 15 years. When I called back, they wanted to try GM's fix as MS3DALE posted (Thanks), I reluctantly agreed and brought the truck in. I requested the truck be put up on the hoist and we go through areas I had major concern over. They did, the General Manager and manager of the guy doing the work went though it with me.
3 days later I picked up my truck and when I got home I decided to have a look. I think my blood started to boil when the areas inside the frame that were rusted bare metal were never done, looked the same as when I dropped off the truck. Other areas by the spare tire (which was never removed evident by the undercoating spray on it) still have obvious issues of rust and loosening coating.
I'm sure they overlooked the TB statement "Important: To ensure proper coating performance, all of the manufacturer’s “Applications Guidelines” MUST be followed.",
because I can see where sprayed areas stop and dust covers frame is right next to it. Now I have a cobbled mess. I called the dealership and they said bring it in again and will redo those areas. I lost my confidence with this fix and feel there is no way it's going to last. GM can have this truck back.
Sorry for being long winded, but venting my frustrations:(
