6.6-Liter LML Duramax Engines. The LML Duramax Engines is a General Motors diesel engine family for light to medium duty trucks. The 6.6-liter LML Duramax Engine is produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. JDB2010 PT 77-0011 GM vehicles have three types of Vehicle Thief Deterrent (VTD) systems, each requiring their own