In June XDP published an informative story on the 2001-2004 GM 6.6L LB7 Duramax. The article begins by noting how the heavy-duty truck scene was altered when Dodge teamed up with Cummins. A dozen years later, GM introduced a diesel engine that would make them a contender in the diesel market. Introduced in 2001, the superior Duramax replaced the Detroit Diesel 6.5L, incorporating state-of-the-art technology.
According to the XDP story, the design of this new engine was initiated four years earlier when GM and Isuzu linked arms to create a partnership called DMAX Ltd. Production of the LB7 commenced three years later. The 6.6L V8 had four valves per cylinder and delivered 300 hp along with 520 lb-ft of torque.
This was a revolutionary engine, with turbocharger, intercooler and direct injection (features that are commonplace today but were not at that time.) Its most significant feature was the use of common rail technology developed by Bosch, a first amongst the big three, two years before Dodge and seven before Ford. The engine was also lighter, with aluminum cylinder heads. Ford adopted lightweight aluminum cylinder heads a dozen years later in its 2011 Powerstroke.
The author places a spotlight on the real "star of the show" for many enthusiasts. The Allison 1000 was "arguably the first automatic transmission in its class worthy of being mated to a diesel." In short, it was a marriage made in heaven.
If you preferred a manual, instead of the 5-speed Allison tranny, you could choose a ZF 6-speed manual. The Allison 1000, however, became the more popular choice.
The new LB7 Duramax was available in some of the other GM brands including the GMC Sierra 2500HD and 300HD, and the medium duty Chev Kodiak and GMC TopKick. In addition to the engine and drivetrain upgrades there were also some new body styles introduced. The author goes into detail on many of these features as well.
The article is actually a Buyer's Guide with XDP noting out the pros and cons of this iteration of the Silverado. The biggest problem had to do with the LB7 fuel injectors. The fuel injector problems were so common that they had a recall to replace them with an updated design. Warranties helped keep GM owners from bailing out completely.
XDP cited the primary pros and cons as follows:
Pros
Allison Automatic Transmission
IFS For a Smooth/Comfortable Ride
Common Rail Fuel System with CP3 Pump
Different Exterior Styling Choices (’01-’02 Silverado, ’03-’04 Silverado, or GMC Sierra)
Cons
Body/Frame Rust
Weak Tie Rod Ends
Brake/Fuel Lines Prone to Rust
Factory Dowel Pin that Holds the Harmonic Balancer in place can Shear.
* * *
The latter part of the article--Popular Aftermarket Upgrades--is really the meat of the story. Everything else is setup, laying the foundation for readers to make informed decisions.
If you have a 2001-2004 GM 6.6L LB7 Duramax, this is a highly informative Buyer's Guide piece that you may wish to read and bookmark. Check it out here: https://tinyurl.com/hz7k6ktc
Related Links
Duramax Diesel Vehicles
Shopping for a Used Diesel Truck? Here's the Best & the Worst
Blue Flame Diesel Oils & other Champion Products at XDP
