TORQUE SOUTH

The 6.6 liter (403 cubic inch) Duramax turbo diesel V8 is made by General Motors and Isuzu. It was introduced in '01 in Chevy and GMC trucks, as well as heavy duty commercial-grade equipment. It remains the hardest working engine for GM trucks today, and the 1,000,000th one was produced in mid 2007. The D-max made it to the 10 best engines list the first two years it was produced, and has been continually and significantly improved since. Some of its mechanical features are 32 valves, high-pressure common-rail direct injection, and aluminium heads. The first generation ('01-'04) was called LB7 (VIN "1") and made 300 horsepower @ 3100 rpm / 520 torque @ 1800 rpm. This generation had injector problems, so GM extended the warranty to 7 years / 200,000 miles. You can tell an LB7 Chevy by the square old school headlights. Second gen ('04-'06, VIN "2") are called LLY and have the newer "eyebrow" headlights, but only say Duramax Diesel on the side without an extra Allison badge. These made 310 hp @ 3000 rpm / 605 tq @ 1600 rpm with the help of a new variable geometry turbo. Some of the early ones had overheating issues, but GM warrantied and quickly fixed the problem. These trucks are mostly trouble free. Interestingly, the '06 LLY is mechanically identical to the bad boy LBZ  (even has the new transmission and computer) with just a weaker tune. Late '06 and early '07 (VIN "D") are the notorious LBZ. They can be identified by their "Classic" body style, extra blue Allison badge, and a slightly louder turbo. With their completely upgraded and fortified engine, tougher transmission and smarter / faster computer they produced 360 hp @ 3200 rpm / 650 tq @ 1600 rpm. They are easy to tune and for the most part have no problems whatsoever. Later in '07 the GMT900 series replaced the GMT800, with a better  box frame,  great riding suspension, completely redesigned body style and new engines. The '07-current trucks with the New Body Style (square headlights) all have the LMM engine (VIN "6") making 365 hp @ 3200 rpm / 660 tq @ 1600 rpm. This is based on the third gen engine but has a better turbo and cooling system and a crappy Diesel Particulate Filter for regeneration. These trucks can be tricky due to the complex new emissions control systems but the truth is they are the best and most high tech, and absolutely fly with the right modifications and tuning. All Duramax are excellent and in their year the competition could not even come close. Note: on GMC versions, they pretty much look the same from '01-'07, except the extra blue Allison badge for LBZs in late '06. In late '07 they also changed to the NBS (new body style, GMT900)