What Years Of Duramax To AvoidThese trucks aren’t built for work. For good reasons, as the LBZ engine was praised by experts and revered by owners, many people gave it a 9/10 rating, which is why I am placing it at the top of this list. A lot of folks on this forum say that the 6. The 2006 to 2007 Duramax was a 6. Lb7 Duramax Years to Avoid. 6L Duramax LB7 used in the 2001 – 2004