Isuzu and General Motors joined forces to create DMAX Limited, which manufactures the Duramax diesel engine. These diesel engines are produced in the city of Moraine, Ohio.
GM is currently the main owner of the Duramax brand. One aspect that is unique in the production of Duramax engines, and almost unheard of in the American automotive industry, is the extensive quality testing each engine has to pass before being shipped out for installation. Every engine undergoes a live test at the DMAX Ltd. facility, where they are put on a test block and allowed to run at operating temperature to make sure everything works correctly.