Diamond Reo Trucks was an American truck manufacturer. In 1967, Diamond T and Reo Trucks were combined to form the Diamond Reo Trucks Division of the 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.
In 1971, Francis L. Cappaert of Birmingham, Alabama, bought Diamond Reo from White. And, at about the same time the Diamond Reo C-116 series was introduced, which featured Cummins NTC-335, NTC-350, NTA-370 and Detroit Diesel 12V-71N engines. Despite new model introductions and excellent reputation Diamond Reo was forced into bankruptcy on December 6, 1974.
One year later Loyal Osterlund and partner Ray Houseal bought the rights to Diamond Reo trucks and made room to continue production in their Harrisburg, Pennsylvania, facility, originally a dealership and maintenance facility. The single model C-116 Giant was continued in production with the Cummins NTC-290 diesel engine as standard power. Production for 1978 was 131 units. By 1985, the Harrisburg plant was expanded to be able to produce 10 trucks per day, although output continued at about two per day. The company continued to build about 150 Class 8 trucks annually through 1995.