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.

Product Review: Most 6.5L diesel owners don't give a lot of thought to the harmonic damper, but the 6.5 and indeed all diesel engines depend on their harmonic damper to produce a smoother running engine and to reduce the destructive effect of harmonic vibrations in the crankshaft. Whether due to age or accumulated mileage, more 6.5L diesel engines are suffering from crankshaft failure - some of which are due to a deterioration of the factory harmonic damper. Until recently, our only choice was the factory damper. Fluidampr's recent release of their viscous damper for the 6.2/6.5 changes everything.

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!

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

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.

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.

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.

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.

Making big power these days requires help to burn all of the fuel provided by the power modules and programs used in competition, and nitrous helps burn that fuel and make more power. If you're after the most Duramax diesel performance, all roads lead to nitrous oxide.

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 USDieselParts.com, and got acquainted with what's new for those looking for gauges and gauge accessories. Let's have a look.

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.

Anyone who has owned a 6.5 for any length of time has had to deal with leaking engine oil cooling lines. Because of age-hardening and countless temperature cycles, all factory oil cooling lines eventually begin leaking at the hose joints. The braided stainless-steel flexible lines and leak-proof hydraulic fittings included in the DSG kit should offer a permanent solution to this age-old problem, and the new high-efficiency engine oil cooler should help to reduce oil and engine temperatures.

Performance tuning/flash programmers appear to be carving out a market with the Duramax performance crowd - and for good reason. Programmers offer a number of unique features that make them a "must have" for any Duramax owner. Here is a brief summary of five Duramax power programmers, and a list of features available for your Duramax.

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.

Product Review: We had to dump the Project truck's original half-ton 10-bolt rear axle. The 8-1/2" diameter ring gear and 1330 U-joint pinion yoke were deemed not up to the task when twisted by a Duramax 6600 producing more than 600-horsepower and 900 lb-ft of torque. Without going the custom (expensive) route for a stronger replacement, we chose the GM 9-1/2" 14-bolt semi-floater for this six-lug application. Once acquiring the axle, we visited the experts at Randy's Ring & Pinion for a professional rebuild.

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.

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.

Product Review: Here in the northern latitudes during the winter months, we spend a lot of time driving to and from work in the dark, and I appreciate all of the illumination a good set of headlamps can deliver. To improve night driving, Diesel Services Group began offering a performance headlamp wiring kit for GM vans and light-trucks (equipped with 9005 (HB3) and 9006 (HB4) bulbs) that provides a significant improvement in headlamp intensity.

Product review: Whether trailering through congested city streets or backing into a tight mountain campsite, towing mirrors are essential. For most of us, the best towing mirrors are of the extendable/retractable variety. This is a compromise we make that provides the utility necessary when driving without a trailer and when towing. Recently, Schefenacker entered the market with their telescopic trailer towing mirrors produced expressly for the 1999-current GM Silverado/Sierra pickups and 2000-current full-size SUV's.

Product review: The Duramax 6600 diesel has a lot of untapped potential - just waiting to be unleashed. We've finally tested the latest performance module from Diesel Services Group for the Duramax 6600 that adds more capability to an already strong running powertrain. Teaming up with Van-Aaken Developments, DSG has developed a Duramax performance module that maintains important powertrain safety features, such as transmission slip protection, while delivering a smooth boost in towing power and awesome street performance.

Product Review: General Motors' 6.6L Duramax turbocharged diesel engine was introduced in the 2001 model year 2500HD/3500 pickup trucks and chassis cabs. Along with the new engine came the Bosch high-pressure common-rail fuel injection system. Fuel pressures as high as 23,000-psi demand much from the high-pressure pump and solenoid-controlled fuel injectors, and the less than stellar quality and cleanliness of the available diesel fuel here in the US may present some durability and longevity challenges for these components. Supplemental fuel filtration may be required.

Product Review: Today's performance air filters must excel at two vitally important and yet polar opposite functions. First, they must allow the engine to breathe without unnecessarily restricting airflow. Second, today's performance air filter is also judged by its dirt capturing ability. Truck owners in the know demand an air filter that allows an engine to perform up to its full potential yet stops virtually 100% of all harmful dust and other airborne contaminants. Creating the perfect blend of unrestricted airflow and maximum dirt stopping ability is the goal of today's performance air filter manufacturers.

Sometimes you don't know what you've been missing in your truck's ride quality till you install a new set of shocks. The factory-installed shocks had just 28,000 miles on them, and given the fact that this is a 9200-lb GVW pickup truck, I thought the original shocks were doing an OK job. Installing a new set of Bilstein shocks let me know what I was missing.

The FSD Cooler is a product whose time has come. The Stanadyne DS4 began as a marvelous concept in electronic diesel fuel injection, but it has produced enough problems for people to warrant a closer look at the most common types of failures. The FSD Cooler featured here offers a cure for many of these problems.

To continue with the technical improvements to my 6.2L truck, I have added an electric lift pump to assist in starting, to be an on-board backup to the engine-driven mechanical lift pump, and to easily reprime the Stanadyne fuel filter on the firewall after routine (or emergency) fuel filter changes. The electric fuel lift pump installation also allows me to complete (and document) the performance improvements I saw after the last performance upgrades. This article completes that story.