The LBZ, also known as the “classic body style” Duramax, was released in 2006 and continued through mid-2007. To easily identify the 06-07 LBZ motor the eighth digit in the vin number will be a “D” which is the engine code. The LBZ is the more sought after model because of its stronger rods, upgraded 6-speed transmission, and improved programming allowing the ability to refine tuning. The LBZ was also the last year to offer then manual ZF6 transmission.
Like in previous years, the LBZ utilizes a high-pressure common rail injection system which needs proper filtration to prevent failure. The factory fuel filter filters down through an 8-10 micron filter but the injector needs about 2 microns of filtration. Injector failure can be prevented with simply installing an aftermarket Fass or AirDog Filtered lift pump system. The LBZ also used basic emission systems such as a catalytic converter and an EGR system which can create their own set of issues. Some of the issues that the previous LLY model had were fixed for the LBZ but not entirely. The LBZ still ran into some airflow restrictions that can be upgraded and fixed. The turbo inlet and hot side intercooler pipe can be upgraded to allow better airflow and drop in EGT’s. The factory downpipe is crush bent and restrictive which leads to an increase in temperatures, so doing a full exhaust with an added downpipe will cure some of these EGT issues.