It would be great if more people used biodiesel in the diesel trucks! However, at least in Michigan, you can not legally sell the biodiesel you make at home and many people do not want to put the time and effort into making it themselves. There are a few negatives to using biodiesel in diesel trucks. First, there is limited availability of biodiesel fuel. Next, the cost is much higher for biodiesel. Also, fuel economy is off by at least 10%. Additionally, biodiesel may be a concern in cold weather and in older vehicles.