Duramax 6600 Volume II

- Now Available! -

The Duramax 6600 Volume II represents a printed and bound collection of the important Duramax diesel and truck related articles, product reviews, and tech columns that were published by The Diesel Page between early 2004 and May 2008 - covering the original 2001 LB7 to the 2008 LMM Duramax diesel. All totaled, there are 38 articles in 133 information packed pages, and illustrated with 305 photos. What you'll find here are time-tested and proven methods, techniques and strategies that will increase Duramax performance, fuel economy and reliability.

This volume begins with 4 articles about the new trucks and powertrains, beginning with the 2005 model-year LLY Duramax and 2006 LBZ Duramax, through to the new emissions 2007 & 2008 LMM Duramax equipped trucks. These articles will allow you to see the evolution of the trucks and powertrains, and see how both performance and styling has changed throughout this period.

The next four articles show you how the Duramax compares with Ford & Dodge during real-world trailer towing tests. Real trucks towing a 10,000-lb trailer on a real 6% grade gives owners and prospective truck buyers the most accurate sense of how these trucks really compare to one another.

The middle third of this volume contains a selection of Duramax & truck related product reviews we've completed during this four year time period. We only discuss products that work, and we show you how they're installed.

The final section of this volume contains a series of Duramax & truck related technical articles that cover some of the more common problems owners have seen with these trucks. When combined with the Duramax 6600 Volume I, we've compiled the most accurate, most comprehensive and most useful technical resource available to the public that focuses on these GM trucks. Thank you!    TDP

Note: This volume is available separately. Please see the Member's Area page to see what articles are currently online and available to current Option A or B subscribers. Many of the articles included in this volume are no longer available online and are not included with a subscription.

Two Thousand Five
New GM Pickup Truck Specs & Detailed Information

We're always looking forward to the mid-year announcements of the upcoming model lineup for GM's 2500HD/3500 pickup trucks. Evolutionary changes to both the exterior appearance and to mechanical/electrical systems enhance function and help improve ownership satisfaction, and the 2005 models continue that tradition. While we tend to focus on the 2500HD/3500 models, you'll find the powertrain specs for the gas engine equipped trucks here as well as those powered by the Duramax diesel.

Two Thousand Six
GM's 2006 model-year Pickup Trucks

The 2006 model-year Chevy & GMC diesel 2500HD/3500 pickups began arriving on dealer lots in August of 2005. While not much has been added or changed to the 2005 model pickup styling or option list, the big news is the new RPO code LBZ Duramax 6600 diesel engine. Go here for a look at the new trucks and to learn more about the new uprated Duramax diesel engine.

Two Thousand Seven
The Face of the Future

GM's 2007 Silverado/Sierra 1500-Series Pickup Trucks

GM has a lot riding on the 2007 model year. With nearly 50% of all new vehicles sold in the U.S. being pickup trucks, this market is something General Motors simply has to do well in. Introduced as a 1999 model, the outgoing Silverado is now eight model years old, and has begun losing ground to the fresh faces offered by both foreign and domestic competitors. Enter the GMT-900, a new for 2007 body style that introduces a long list of refinements in addition to all new sheet metal. Included here are new photos and information about the new 1500 series trucks, and we'll discuss how the design features shown here could appear in the upcoming 2500HD/3500.

2007 Duramax LMM
The New Emissions System

The new VIN code 6 2007 LMM Duramax equipped trucks have arrived, and along with them the new DOC/DPF (Diesel Oxidation Converter/Diesel Particulate Filter). Changes in the emissions system are the big news, and this article should help to explain what's new & different and shine a light on what LMM owners need to know to have the fewest problems. Go here to see original photos of the new emissions components, and learn how these components function. Do we need to worry about the 2007 emissions systems?

The Diesel Page
Pull-Off V - July 2004

GM, Ford or Dodge? - Determining Braggin' Rights!

The truest test of diesel pickup performance can only come when run on a real hill and with a real load. After all, most diesel pickup buyers bought their truck to tow trailers. Launching from a dead stop, then running full-pedal with a 10K+ loaded trailer for a measured mile on a 6% grade helps to separate fact from ad hype.

The Diesel Page
Pull-Off VI - July 2005

Shock & Awe

Pulling uphill against a 10,000-lb trailer for 50+ seconds separates the dyno or 1/4-mile trucks from those that rule the Pull-Off. Simply put, unless puddles of molten metal are your goal, an extreme horsepower Duramax/Powerstroke/Cummins won't be able to use all that power for the time it takes to cover a measured mile on a 6% grade with a 10,000-lb trailer in tow. Most diesel pickups are bought with the intention of towing a trailer - at least part of the time. Makes sense to construct an event that focuses on real-world towing performance. Measuring engine and drivetrain performance on a real hill and with a real load is in essence what a Pull-Off is all about. Each Pull-Off has two primary objectives: 1- To learn how stock diesel pickup performance evolves with each new model year, and 2- Track the performance improvements made possible by the aftermarket. The Pull-Off is simply the best way to measure the towing performance of a diesel pickup truck.

The Diesel Page
Pull-Off VII - July 2006
The Duramax Raises the Bar - Again!

A looming grade can either induce dread or anticipation; depending on whether you're driving the highest rated diesel pickup the "big three" have to offer. Included here is an accounting of the 12 trucks that pulled the hill this year, which included 4- Duramax's, 4- Powerstrokes, 2- Dodge Cummins, and 2- 6.5TD's. Find out what truck is the King of the Hill for 2006.

2007 Chevy -Vs- 2007 Ford
Tow testing the new emissions LMM Duramax and 6.4L Power Stroke

A recent pickup truck ad said: "Truck guys will tell you taking off with 10,000-lbs ain't no picnic. Stopping 10,000-lbs ain't no picnic either." We agree. Towing tests are few and far between in the automotive media. Most of what we see are dyno results, 1/4-mile elapsed times, and generalized reports about on-road capability. Those types of tests can provide some clue about what we might expect while towing a heavy trailer, but they fall short of a real towing evaluation. Part of what most potential GM & Ford buyers really want to know is how the newest diesel pickups stack up against one another in a real-world towing test on a real hill while towing a trailer that weighs at least 10,000-lbs. That's what this test was all about.

1 Million Duramax 6600 Diesel Engines

After six years and nine months of continuous production, DMAX Ltd., the maker of the Duramax 6600, celebrated producing its 1,000,000th engine on April 16, 2007. According to DMAX, they can sell all of the engines they produce and more. Go here to see the story and learn more about what makes the Duramax 6600 so successful.

ZF S6-650 Six-Speed
Manual Transmissions for GM's HD Pickups

Control, economy, and performance are the primary reasons why truck owners choose a manual transmission over an automatic. The ability to choose just the right gear for either pulling or descending a grade are important factors that allow a truck owner to maximize pulling power and improve overall powertrain efficiency. A manual transmission gives them that level of control.

Edge Juice w/ Attitude Monitor
Making the Duramax Rock - Part I

Product Review: You hold in your hands one of the most remarkable power upgrades available... So begins Edge's product description on the back of the box. After having spent some time with the new Juice/Attitude, I tend to agree. In addition to the 5-level 0-150 horsepower increase (depending on model) available at just the touch of a button, the Edge Juice with Attitude monitor combine to produce a truly comprehensive engine performance package for the Duramax diesel.

Performance Traction Bar System

Product review: Big power can stress unmodified chassis and suspension components in ways that limit overall truck performance. Pushing quarter-mile times into the 13's is relatively easy. Going faster requires more power, more effort and more attention to chassis setup. The recent installation of Kennedy Diesel's traction bar system in our Duramax Diesel hot-rod is a step toward the 11's.

Banks Big Head
More Boost for the LB7 Duramax 6600

The key ingredients to more turbodiesel power are more fuel and higher boost pressures. The Banks Big Head incorporates an adjustable turbo wastegate linkage, allowing you to raise boost pressure to get that power increase.

Got Gauges! - Reloaded
Gauge & Gauge Accessories

The number of different gauges and gauge accessories has grown considerably since our 2002 gauge install piece. I recently stopped by to see the folks at, and got acquainted with what's new for those looking for gauges and gauge accessories. Let's have a look.

KD Fuel Pressure Gauge
for the Duramax 6600

As diesel fuel injection systems become more complex and more sensitive to fuel quality, owners have become more tuned-in to the nature of diesel fuel systems. Being able to check fuel pressure (vacuum) can help an owner diagnose a future problem or allow him to monitor the condition of the fuel filter in an on-going basis. This not only can save you a lot of frustration in the high-stakes game of vehicle service, but can save you money on fuel filters by not replacing them till the fuel restriction gauge tells you it's time.

Got Boost?
KD Boost Valve for the 2001-2004 LB7 Duramax 6600

There's an old saying that says "offer a great $5 part that installs in 5 minutes, and you'll sell a million of them." Well, the KD boost valve might be a little more than $5, but it is still inexpensive, installs in minutes, and offers a lot of bang for the buck. This simple device increases maximum boost pressure about ~5-8 psi, and makes the factory LB7 turbo a lot more responsive under all operating conditions. Combine this with any one of a variety of Duramax power mods, and you'll see an even bigger improvement in power than what a power mod by itself delivers.

Universal Auxiliary Fuel Filter
For the Duramax 6600

Fuel Quality can determine whether your diesel fuel injection system provides typical service or whether you are plagued with frequent visits to the dealership. GM recently upgraded the factory fuel filter element in an effort to help protect the Bosch high-pressure common-rail fuel injection system used by the Duramax 6600. Trapping more and smaller particles in the fuel can improve both fuel quality and injection system longevity. Lubrication Specialist Greg Landuyt has developed an easy to install and cost effective auxiliary fuel filter kit that can add a significant safety margin to the diesel fuel you're using.

ATS Allison Extreme
Performance-Built Transmissions

Product Review: The Allison 1000-Series 5/6-speed transmissions are simply the best and most durable automatics to ever have been installed in a pickup truck. When using stock power, it's practically impossible to hurt the transmission or exceed its torque handling capability. As good as the Allison is, however, it's still possible to exceed its torque handling capability when using a power adder. Most Allisons will hang onto the power up to at least 75 additional horsepower and 200 lb-ft of torque, but living on the ragged edge can take a toll on long-term durability. This is why installing a performance-built Allison can increase the fun!

Custom Programming
the LB7 Duramax ECM
More Power - Better Fuel Economy!

The various electronic power products have done a remarkable job of increasing Duramax diesel performance, but till now, we've had to accept whatever programming or tuning options were offered by the aftermarket. The recent appearance of custom ECM (Engine Control Module) programming has increased the number of options for nearly every truck owner, whether they're looking for a few more miles per gallon, a safe towing program or a killer track tune. Kennedy Diesel is now offering custom ECM tuning, which provides for a host of additional programming features.

Custom Programming
the LLY Duramax ECM

Last time, we showed you how to update the 2001-2004 LB7 Duramax ECM with one programmed for more power & better fuel economy. This article looks at programming 2004.5-2005 LLY Duramax ECM.

DIY Cold Air Intake for the LLY Duramax

After considering all the various cold air intakes systems available for my truck, I decided to develop my own, which only cost a few dollars and an hour or so to complete. Keeping the intake air as cool as possible improves power and may improve fuel economy. While inexpensive, this modification retains the excellent filtering ability of the stock air intake system.

2006 Mirror Upgrade
Easy upgrade to GM's 2006 Mirrors

I recently upgraded the stock mirrors on my 2005 GMC 2500HD to the 2006 model trailer towing mirrors. Although the stock mirrors extended for trailer towing, I was not happy with the narrow field of view the stock mirrors provided. For the 2006 model year, GM released a new style extendable towing mirror, similar to the Ford SD towing mirrors. Go here for a photo illustrated step by step guide to installation.

2001-2007 2500HD/3500

Transfer Case Leak Prevention

For several years now, we've been hearing reports of transfer case fluid leaks due to a wear-through on the rear case half. If not caught before a leak develops, the transfer case could suffer complete failure due to a lack of lubrication. The most reliable solution includes installing an aftermarket part that prevents a case wear-through from happening. Follow along as we show you the problem and describe what it takes to produce a permanent solution.

Towing EGTs
Does Adding Power Increase EGT?

The short answer is "not always". I had an opportunity earlier this year to perform a series of towing tests, comparing stock exhaust gas temperatures to those while using a VanAaken performance module for the LB7 Duramax. We've all seen the admonitions for installing a set of boost pressure/exhaust temperature gauges and a performance exhaust system before adding power. This has been and remains excellent advice, but more people than you know have added power while maintaining the factory exhaust system. Go here to find out what really happens.

LLY Duramax 6600 Marine Diesel

Our marine diesel project included installing an 2004 LLY Duramax 6600 in a 1983 26' Corsa offshore race boat. The engine is mated to a Borg-Warner Velvet Drive transmission and a Mercruiser Super Speedmaster III drive. Working through the electrical/electronic issues for such a conversion was perhaps the most daunting, but this may be the first privately owned marinized Duramax 6600.

FMC Motor Home
Duramax/Allison Conversion

From 1972 to 1976, approximately 1200 2900R motor homes were produced by FMC at their Santa Clara, California facility. These were true luxury coaches for the day, incorporating some unique features like a rear mounted engine, 4-wheel independent suspension, perimeter frame, and aluminum main structure. When compared to other coaches, the FMC drives more like a passenger car, and the power and fuel economy with the Duramax are incredible.

Pro-Stock Duramax Diesel

Seemingly overnight, diesel drag racing has swept the nation, and is becoming more popular as each racing season passes. To help fill the need for speed, more retired Pro-Stock drag race trucks are being brought out of retirement, but not to run blown nitro burning bigblocks. Nope... The trucks are rocketing down the track with the state-of-the-art in diesel performance. Brad Makinen brought new life to a retired gas Pro-Stock truck in the form of "Dirtymax", a Duramax diesel powered Chevy 1500. This truck appeared at a drag race event I attended this past June here in Montana, which provided an opportunity to look beneath the fiberglass skin to see what it takes to make a Pro-Stock diesel run in the 8-9 second range.

Magnum Force
Performance Air Intake Systems by AFE

for the Duramax Diesel

Product Review: Squeezing the last bit of performance out of a turbo diesel involves improving exhaust flow and intake airflow. Performance air intake systems are the best way to help your engine breathe, and AFE produces a line of products to help achieve maximum intake air flow. Documenting performance improvements using a chassis dyno helps answer many questions, and we thought you might be interested to learn what we discovered after installing an AFE Stage II performance air intake system on our 2001 GMC 2500HD equipped with the Duramax/Allison.

Electrical Junction Block - Body
Accessory Electrical Power Inside the Cab

The electrical junction blocks (both under the hood and inside the cab) can be used to provide power for a variety of switched and non-switched accessories, and you can take advantage of these as well for installing a brake controller or providing a dimming lamp source for your accessory gauges. The illustration included here is of a 2001 model-year electrical junction block, which is located near your left foot when seated in the driver's seat.

Air Conditioning Service

Part of the mystery in servicing automotive air conditioning systems for most people is a lack of understanding in the technology. While it does require specialized equipment and training to know all that is knowable, acquiring a basic understanding of what the various system components do and learning how they work together to produce cool air inside your vehicle will help in maintaining your A/C system - whether you do the work yourself or choose to hire the professionals. Go here to learn how to evaluate and recharge R-134a GM A/C systems.

Allison & Drivetrain Tech Tips
4 Wheel Drive Front Axle Lube

Shift quality observations and a new front axle lube requirement.

Solving Allison ATF Leaks
No Leaks, No Drips - No Errors

We hear of Allison fluid leaks every once in a while, and have recently experienced one ourselves. Most of these leaks result in automatic transmission fluid dripping off the bellhousing area of the transmission. An input shaft seal problem probably comes to mind first, but as we've learned, these seals are rarely the cause. Follow along we show you what to look for and how to repair a leaky Allison.

Service 4WD
Selectable 4WD Problem
& Easy Fix

A bright yellow Service Engine Soon or Message Center warning usually means trouble. Luckily, this "Service 4WD" Message Center warning light often means you'll just need to replace the pushbutton switch panel that controls the NV-263 selectable-shift transfer case (RPO code NP1). Go here to find out how.

2006 Duramax LLY/LBZ Service Recall
Addressing a possible glow plug failure.

In an effort to reduce cold-start induced white smoke, GM has upgraded the glow plugs, the glow plug controller and the ECM programming on a continuing basis since first introducing the first Duramax 6600 in the fall of 2000. The 2006 Duramax, identified as either RPO code LLY (early '06 models) or LBZ (late '06 models), saw another glow system upgrade. Faster-acting glow plugs and shorter cycle times combine to further reduce white smoke after a cold start, while helping to make diesel engine operation more transparent to those more familiar with starting a gas engine. However, there have been a few bumps in the road regarding the 2006 glow system.

Duramax & 2500HD/3500 Truck
Technical Service Bulletins

Here, you'll find 43 of the top GM Technical Service Bulletins pertaining to these trucks and the Duramax/Allison drivetrain. Included are the bulletin number, the title and a summary for all 43 listed bulletins. This compilation contains great information you need to know.

For the Duramax

Learning more about turbocharger theory can help the performance-oriented Duramax owner achieve a level of cool-running and long-term performance beyond that provided by the factory turbocharger.

Duramax Tech
Broken Turbo Downpipe Bracket

I had the exhaust system off my '01 GMC recently and noticed that my truck's downpipe bracket had broken. Find out how to inexpensively repair this somewhat common problem.

2001-2004 Duramax Diesel
Excessive Fuel Return Flow & Related DTCs
P0089 - P0093 - P1093

The Diagnostic Trouble Code P0093 applies to the 2001 model-year Duramax. This trouble code was updated for the 2002-2004 model year engines, and received a new number - P1093. Each refers to the same problem. P0093 & P1093 are defined as "Fuel System Large Leak Detected", which could mean that one or more injectors are experiencing a high fuel-return flow rate. People usually start looking beneath the truck for signs of fuel, but this isn't that kind of a leak. Let's have a look at these, and other related trouble codes, to provide a little more insight into what they mean and how to deal with them.

- Now Available! -

To order the Duramax 6600 Volume II, please visit our on-line Membership application/book order form or give us a call at 1-406-777-3675 M-F 9-6 mountain time. $24.95 + shipping to US addresses (USPS Priority Mail rate).

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