New GM medium duty trucks, available with 4x4. January 25, 2019, 06:08:14 pm GM introduced a new medium duty series, long overdue after the Kodiak chassis went away.Silverado 4500, 5500 and 6500, with a Duramax 6.6 diesel, Allison transmission and 4x4 option.Would make a nice platform for an all season Lazy Daze RV. Joint effort with International, who gets a version and makes the truck for GM at a plant in Texas. 2 Likes