Try this site out I had some issues getting into it. But theres a boatload of info ordering options, truck options, technical data....etc
If it doesnt work Yahoo ecomm gm and the site is the first match you will see.
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!