I was hauling bales with the truck, filled the gas tank for the next day... Next morning I noticed a darkspot under vehicle and noticed it leaking Gasoline...After some investigating and talking with our local mechanic, and taking it there, we discovered the fuel tank completely sucked together causing it to leak... Apparently, instead of putting a vented gas cap on, Chevrolet put a computer controlled valve(which malfunctioned, not letting fuel tank get air) we had to have the fuel tank replaced, and the vent valve fixed.. As well, the mechanic fixed the cap so it could vent also!!! costing a fairly large sum of money, can't recall exact amount but over $1000.00 (Canadian)...It would have been better for Chevrolet just to keep using vented gas caps...