DMAX is an American manufacturer of diesel engines for trucks, based in of Moraine, Ohio. DMAX, originally announced in 1997, is a 60-40 joint venture between and operated by General Motors and Isuzu. Diesel engine production started in July 2000. The company's Duramax V8 engine has been extremely successful for GM, raising that company's diesel pickup market share to 30% in 2002, up from approximately 5% in 1999. The DMAX plant was built on a land grant site adjacent to a GM plant that made the 6.2/6.5 L Diesel V8. Production of that engine began in 1982.