Diamond Reo Trucks is an Australian truck manufacturer, formerly American. In 1967, Diamond T and Reo Trucks were combined to form the Diamond Reo Trucks Division of White Motor Corporation. Reo dated back to 1904 when Ransom E. Olds, founder of Oldsmobile, began building motor cars, and Diamond T dated back to 1905 when C. A. Tilt began building vehicles.