Just in case you are interested, there is a locking gas cap for the 2007.5 Chevy Silverado Diesel. I just put one on yesterday (although you can't use the tether). I ordered it through www.autosportcatalog.com (http://www.autosportcatalog.com) and it is a Stant (#10591). The reason I am posting this is that I was told that there is no locking cap for my particular model. Well - the only problem is that it is not green and it does not have "diesel only" on the cap. It is however a perfect fit. Since Autosport lists it as a cap for the truck, it seems to fill the bill (unless someone has knowlege why this cap shouldn't be used). Just thought I'd post this.