Being concerned over the rust in my original fuel filter, I decided to send of an e-mail to GMC customer service. A GM rep just called me today and wanted to know more about the situation. I explained that I was concerned about the rust in my original filter and any impact it could have on my engine. The GM rep recommended that I take the filter in to have the dealer look at it. The rep was not aware of any problems with the filter. She thought perhaps the truck could have been sitting on the lot for a long time before I purchased it - thus the rust (I had to bite my lip to keep from laughing on that comment). Anyway, now I have to go to the dealer and get their expert opinion. I know how this is going to turn out - to be a big waste of my time. Of course, I don't expect any insight from the dealer.