The Duramax is a General Motors diesel engine family for light to medium duty trucks, designed by GM and Isuzu. The 6.6-liter Duramax is produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. The Duramax block and heads are poured at The Defiance GM Powertrain foundry in Defiance, Ohio. This engine was initially installed in 2001 model year Chevy and GMC trucks and has been an option since then in pickups, vans, and medium-duty trucks.