Buy Amsoil Synthetic Lubricants Factory Direct from Amsoil Dealer - Synthetic Oil AMSOIL Dealer Brian Dobben Presenting the Gold Standards in Lubrication and Filtration: Ultimate Fuel Economy, wear protection, environmental benefits and performance.

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Expert Advice For YOUR Specific Application


We DARE you -
the Ultimate Synthetic Oil Challenge


Converting to AMSOIL & Breaking in a New Engine - Please Read This Critical Information


Amsoil Retail Product Catalog

Download Newest Amsoil Product Catalog
(~2.5 mb pdf)



Get Your FREE Special Reports on Superior Vehicle Maintenance for Less Money

- we include important insider vehicle engineering facts that OEM's don't even tell their dealership mechanics ! 



Drive it for
a Million Miles like this 1999 Chevy Express 5.7L hits 1 Million miles on Amsoil

How does YOUR oil perform against Amsoil? See full 2009 Comparative Engine Oil Testing Report  

See How You Can Lower Your Vehicle Maintenance Costs to FREE


"Scamsoil Skeptics Corner

Revealing the boldest skeptic's questions... and our engineers' answers


Research Study Released -

September 2007! 

Since your whole tow load rests on TWO gear teeth, How can you save your "Diff" from failure? 

Hauling or towing?  How long do you want YOUR Differential to last?

Read the Free

Differential Gear Lubes Research White Paper (482 kb)  

Most of the 14 Name-Brand Gear Lubes Tested FAILED Specification Tests - is yours one of them? 



Free brochure on the Ultimate filters for engine oil and air (1.3 Mb pdf)


New CJ-4 Oil for the new 2007 Diesels


Fuel Economy:  Our exclusive Ultimate Guide to Improve Your Fuel Economy

(Updated again May 2009)


Boost your MPG -
See controlled test fleet average an 8.2% increase in fuel economy!


Breakthrough:  Nanofiber Air Filters use no oil, last over 100k miles, flow like oiled gauze, AND are 100% efficient
 at 3 microns!!!


NEW ! 

New AMSOIL EaAU Replacement Nanofiber Air Filters for Most Popular Air Induction Kits


What Product Do I Use?  When Do I Need to Change My Amsoil Oil or Filter? 

Oil & Filter Application Guide (PDF)


NEW ! 

New AMSOIL EaBP Nanofiber BYPASS Oil Filters are 98.7% efficient at 2 microns: take out more soot than any other filter!


Nanofiber Full-flow Oil Filters

Last 1-Year/25,000 Mile


AMSOIL AFL meets VW 505.01 and all Euro specs for gas/diesel/turbocharged>


26 Motorcycle Oils Tested: AMSOIL makes Motorcycle History with the most Comprehensive, Authoritative Research Study ever done (1 Mb PDF)






Duramax Diesel Owners


Ford PowerStroke Diesel Owners

Dodge Cummins Turbo Diesel Owners



The Importance of Engine Filtration


Military / Aerospace NanoFiber filtration for YOUR VEHICLES:

Nanofiber AIR Filters:

100% at 3 microns, last 4-Years/100k Miles


Nanofiber OIL Filters

Last 1-Year/25k Miles


Cold Air Induction - Nanofiber Replacement Filters for Popular Cold Air Intake Systems


Bypass Oil Filters run 2-Yrs/60,000 Miles: 

98.7% at 2 microns is better than any competitor






Get Your Oil Analyzed by a Lab (pdf)


GM Reveals Oil Change Intervals Average 8,500 Miles with Oil Life Monitoring System (OLS) (pdf)


3,000 mile oil changes?!  What a rip-off!  GET REAL with modern technology.


Warranty Laws You Need to Know


Informative Articles Must Read!


The Auto Industry's Best Kept Secret REVEALED!

Technical Properties of Oils & Lubricants:
 About the ASTM and API Tests, and What the Test Results Mean

The Facts About
Aftermarket Oil Additives


API Comparative Motor Oil Testing


North American Engine Oils may be Harmful to European Engines

Which 30-weight Oil to Use:  0W-30, 5W-30 or 10W-30, with Discussion of Viscosity Basics

Ford & Honda's 5W20 Issue

Ten Myths About Synthetic Lubrication

Oil Color, Lubrication Ability and Contamination Level





AMSOIL vs. Mobil 1


  Compare AMSOIL to the "top" name-brand synthetic oils

Frequently Asked Questions





Converting to AMSOIL & Breaking in a New Engine - Please Read This Critical Information



Exxon-Mobil FINALLY follows AMSOIL's 33-year-old introduction of Extended Drain Intervals - kinda sorta


Wholesale Dealership and Preferred Customer Opportunities


Home Business and Financial facts


AMSOIL Introduces Four New Two Cycle Oils


Expert Advice For YOUR Specific Application


Satisfied Customers








12 Standardized Tests on 26 Motorcycle Oils: the most Comprehensive, Authoritative Research Study in Motorcycle History (1 Mb PDF)


 AMSOIL Quality Impresses Harley Riders

Harley-Davidson Oil & The Low Quality of OEM Oils

Why Harley Owners Choose AMSOIL!


Harley-Davidson AMSOIL Application Guide

Synthetics, Slipperiness and Wet Clutches  - Simply Not an Issue




Authorized AMSOIL Dealer Website


Links Index


Other Website Links


If you want to buy AMSOIL Products, visit the AMSOIL On-Line Store



Duramax Diesel Owners


AMSOIL offers superior lubrication technology for your Duramax Diesel engine. This extensive webpage will help you learn how to best care for the Duramax, including the options for fluid and oil change service intervals, as well as learning what GM and most servicing dealerships don't want you to know about AMSOIL synthetic motor oil and filtration technologies. You'll see recommendations and options for bypass oil filtration systems, and even a video to demonstrate how easy it is to take an oil sample from your truck for analysis testing. And at the bottom is a special Duramax Owners Questions and Answers section - our engineers welcome your Duramax questions and give valuable answers.

This information comes straight from experienced Truck Engineers and Lubrication Specialists based out of the auto and truck engineering and manufacturing capital of the world - Detroit, Michigan.


We are diesel engine, powertrain, chassis and component experts, and are here to help you achieve optimum performance and longevity from your Duramax truck.

 (which oil should I use?)


Click here for a proven way to
Boost fuel economy by an average 8.2%


You've spent your hard earned money on the Duramax Diesel option in one of the most popular and well engineered trucks there is, now don't you think you owe it to yourself to use the very best oil in it? Your turbocharger needs a good synthetic oil for long life!  Petroleum oils CAN'T do that job as good.  In addition, you need high-performance synthetics throughout your engine and drivetrain to maximize your Duramax fuel economy and enable you to tow without transmission or differential failures.  What should your oil drain interval be?  That depends completely on the performance and condition of your oil and filtration, which is something you can control. 


Don't let your local dealership service center tell you that you you have to use their brand of oil to "maintain your warranty".  That is one of the biggest untruths we have heard, yet it goes on day in and day out.  We constantly receive calls from customers that were told this by their servicing dealership. Please be aware that this practice is not authorized or condoned by the auto manufacturers.

For a servicing dealership to essentially tell a customer that they have to use a lower quality oil to "maintain their warranty" is not only wrong but it is also illegal unless they provide it free of charge. There are Federal laws that protect you against this. Please read our "Warranty Laws You Need to Know" section of this website to learn more.


Specifically for the Duramax Diesel


For the Duramax Diesel, AMSOIL engineers and manufactures a fuel efficient Series 3000 5W-30 Synthetic Heavy Duty Diesel Motor Oil, a 15W-40 Premium Heavy Duty Diesel & Marine oil, and a new 5W-40 Premium Synthetic Heavy Duty Diesel Motor Oil that exceeds the CJ-4 specification for the new 2007+ Duramax engines with Diesel Particulate Filters (DPF's).  (which oil should I use?)  When used in conjunction with the AMSOIL Ea nanofiber engine oil filters, the first two oils will allow you to travel 1 year or 25,000 miles minimum between oil and filter changes. This has been firmly established by extensive oil analysis testing and millions of fleet miles. In fact, if you use oil analysis you can usually go much longer than 25,000 miles on the oil in a year's time. 


However, the 5W-40 (CJ-4) is recommended for use at the longest GM/Chevy oil-drain interval in the manual.  Due to the lower TBN of the DEO's low ash CJ-4 formulation, longer drain intervals will require oil analysis sampling until more data can be collected on extended drain interval performance.


Other AMSOIL benefits include reduced sludge and depositWhich Oil Should I Use? formation, extreme temperature protection, improved fuel efficiency and rust and corrosion prevention - and of course it does not void any newHow to Prevent Turbo Failure vehicle warranty. AMSOIL Synthetic Lubricants meet and exceed all API rated and GM Specifications.  In fact, these lubricants are so advanced that they've typically met/exceeded nearly every OEM manufacturer's published diesel oil test standard, worldwide, without any reformulation


What can you expect when changing your Duramax 6.6L to
Amsoil's superior synthetic diesel oil?

My 2002 Duramax always idled at about 40 psi oil pressure when warm, and pegged somewhere over 80 psi when first started up.  After the engine flush procedure and change to Amsoil's 15W-40 (the same viscosity it always had), oil pressure immediately dropped to about 28 psi warm idle, and about 60-80 psi cold.  Blending over time to the 5W-30 AMSOIL HDD, my warm idle pressure has dropped to about 23 psi.  Some people might be alarmed by this lower oil pressure, but it's a great sign: it means that more oil is flowing through a cleaner engine - for better lubrication, better wear protection, better engine cooling - and it's taking less power (fuel) to pump that oil.


The Secret Power of Nanofiber Bypass Filtration

The BEST option for lowest maintenance costs and downtime is to install an AMSOIL Dual Remote By-Pass Filtration System. With this nanofiber technology system you eliminate over 90% of engine wear, and only change your oil when oil analysis indicates a need. The full flow EaO filter is changed at 15,000 mile (severe service) or 25,000 mile (normal service) intervals and the EaBP Bypass filter is changed at a minimum of 60,000 miles/2 yrs (or longer with oil analysis).

I have over 70,000 miles on the oil change in my diesel Duramax truck [using the Amsoil Dual Remote Bypass system], and I do oil sampling analysis.  Look here at one of my 6.6L Duramax oil sample reports and you'll see that I have no TBN or viscosity problem, and wear rates are very low.  And fact is, I probably will never have a problem, even though I'm changing only my oil filters - not my oil.  In this video I used my own Duramax truck to show you how easy it is to pull an engine oil sample for analysis:

  See this video on YouTube

Oil analysis can also be valuable without bypass filtration.  When using AMSOIL nanofiber Ea Air and Oil filters, analysis will usually allow extending AMSOIL drain intervals far beyond the guaranteed 15,000 (Severe) or 25,000 mile (Normal Service) drain intervals.

Safely Extend Oil Drain Intervals With Zero Warranty Issues:
Download our Free Guide to Oil Analysis Sampling


Need an Oil Analysis Kit or sampling pump?

Visit our Oil Analysis Store

For most gas or pre-2007 diesel vehicle applications using AMSOIL synthetics and nanofiber bypass filtration, oil analysis will show that you NEVER need to change your oil again - even after 500,000 miles! 

How is this possible???  Simple: by using oil that is designed to not break down, and using nanofiber filtration that removes all wear particles, there is no longer a need to change oil.  The oil is so tough that just topping off the oil level when changing filters is enough to renew the additive package.  This saves a lot of downtime, as well as money, and uses about 80% less motor oil - which benefits both your wallet and the environment.

The AMSOIL 15W-40 Premium Heavy Duty Diesel & Marine oil and Series 3000 5W-30 Heavy Duty Diesel Motor Oil do not break down like conventional petroleum based motor oils, are much more shear-stable and do not have the waxes, paraffins and by-products that come out of crude oil that is pumped from the earth.  Which oil should I use?

The by-pass filter removes the particles that cause wear in your engine down to less than one micron (a micron equals 0.001 mm) and keeps the engine oil analytically clean so you do not need to change your oil for a long time, while still getting far better protection than someone that changes their oil every 3000 miles.  We are experienced at installing these units on Duramax Diesels and can provide you with exact installation instructions, tips, a special custom mounting bracket, and photographs of previous installations.

One of the Power Stroke Diesels in our dealer group has over 84,000 miles on the same oil as of November 2003. Laboratory oil chemical analysis every 15-20,000 miles indicates the oil is perfectly suitable for continued service. Other customers have traveled well over 100,000 miles and oil analysis still indicates no oil change necessary. We will mail you a copy of this vehicle's oil analysis results with your product and technical information package so you can see the data for yourself.  My personal Duramax 2500HD CC/SB has the bypass system and has traveled 77,000 miles with only filter changes, as of April 2008. Here's one of my 6.6L Duramax oil sample analysis reports.

In addition, the AMSOIL By-Pass filter will also remove up to a pint of water from your vehicle's lubrication system, which is especially important in a diesel engine. Without this the water promotes rust, corrosion and rapid wear. Internal engine heat also creates acids which also wear the engine components. The water and acids build and continue to work destroying your engine even after engine shutdown.

Oil analysis provides a big return for a small investment by: extending equipment life by preventing premature component failure; reducing maintenance costs by eliminating unnecessary component changes and a decrease in downtime due to premature scheduled maintenance; enabling calculation of optimum drain intervals that will reduce lubricant costs and assure maximum equipment protection.

A regular full flow engine oil filter will only remove wear particles down to the 20-25 micron range, while an AMSOIL full-flow Ea filter removes the majority of particles in the 7-20 micron range with 98.7% first-pass efficiency at 15 microns. But a full-flow filter simply cannot remove all the finer particles because the oil must be filtered quickly while removing most of the particles present in the oil.  That leaves some particles below the 20 micron range. A study completed by Federal Mogul Corp. analyzing over 7000 main and connecting rod bearings concluded that 60% of all engine wear occurs in the 5-20 micron range. This is why no matter how much you change your current full flow oil and filter, regardless of brand, that you still are not removing many of the particles that cause the greatest wear in your engine.

Extensive testing shows that AMSOIL Ea Oil Filters achieve a near-perfect absolute efficiency rating. The exclusive new technology used in AMSOIL EaO Filters provides filtering efficiency to 98.7 percent at 15 microns, and 50 percent at 7 microns. EaO Filters are the most efficient full-flow filters that are available for auto/light trucks, period.

Q: How do EaO filters compare to the full-flow SDF filters that AMSOIL offered for many years?
A: AMSOIL SDF Filters are not quite as efficient as an EaO: filtering efficiency was 94.3 percent at 15 microns and 51.2 percent at 7 microns. The AMSOIL SDF full flow filters had a finer synthetic cellulose filtration media, 75% greater efficiency and up to 300% greater capacity than other popular oil filters, as tested according to the Society of Automotive Engineers (SAE) HS806 test method. The new Ea filters, with nanofiber technology, are even better.

Now, back to considering the new nanofiber bypass filters, which are used in addition to a full-flow filter.  AMSOIL EaBP Filters are high efficiency bypass filters with 98.7% efficiency at two microns. They also remove soot, providing the ultimate in protection against wear, oil degradation and corrosion: your diesel's dipstick will show remarkably clean oil, slightly darker than from a gasoline engine.  Most importantly, you virtually eliminate engine wear, because the wear particles are filtered out of the oil. 

A complete BMK-17Ea AMSOIL Dual Remote By-Pass Filtration System kit costs about $300 or less with the Duramax bracket included, so it is a very cost-effective improvement that will pay for itself quickly.

If you choose not to install the Dual Remote by-pass filtration system then the AMSOIL Ea full flow engine filter would be of a significant benefit to the long term durability of your engine as well as allowing for 25,000 miles of service on the filter.  When you check your oil level every 5,000 miles or 3 months, all you have to do is check the oil level and top it off - don't drain it or change the filter. (Ignore the OLS Oil Life System - don't use it, except to remind you to check your oil level.) When you reach 25,000 miles/1-year you can either change the oil and filter or take an oil sample from the dipstick tube using an AMSOIL sampling pump and send it into Oil Analyzer's Inc. using a pre-paid kit. Oil analysis will indicate the exact condition of the oil and whether it is suitable for continued service as well as determining if there are any other engine components or wear items that you need to be concerned with.

AMSOIL has a complete line of synthetic oils, greases, transmission fluids, gear lubes, Ea nanofiber air filters, by-pass and full flow filters and filtration systems designed to extend the life of your vehicles and equipment and save you time and money. In addition we also offer a preferred customer purchase option, retail purchase option or commercial account purchase option for businesses. Finally, we also offer a Dealership Option for anyone interested in becoming an AMSOIL Dealer and/or purchasing products at wholesale cost.


How to Reduce or Prevent Turbocharger Bearing Seizures on Duramax Diesels


One of the many specific areas, on turbocharged Duramax Diesel engines, that can clearly benefit from the use of synthetic oil is the turbocharger.  When a turbocharged engine is shut off immediately after use, bearing "heat soak" occurs due to the heat that naturally flows out of the hot exhaust manifold and into the turbo, adding to the high temperatures still present in the turbocharger: all this heat "soaks" into the bearings which are no longer being cooled by a flow of engine oil.  Over a period of time this can lead to deposits that can reduce or block the oil flow to the turbocharger bearings, which can lead to turbocharger bearing seizure.


The hotter the outside temperature and the heavier your load, the greater the risk to your turbocharger's life.


To combat these problems and give your turbo maximum life, our engineering staff recommend two things: 1) use of a turbo cool-down timer, and 2) one of AMSOIL's Synthetic Diesel Oils (listed below).  A cool-down timer gives your engine a chance to lower the EGT (Exhaust Gas Temperature) to a safer level before the engine shuts off.  A true synthetic oil does not break down and form deposits in the same temperature range as petroleum ("mineral") oils.  Of these two, the most important is to make sure your Duramax engine oil is a high-quality true synthetic.

AMSOIL's Synthetic Diesel Oils are inherently more thermally stable than most diesel oils on the market, and have been shown to keep turbochargers considerably cleaner than other brands of oil. In fact, AMSOIL synthetics have a noted historical reputation for maintaining turbochargers in a clean like-new condition.  Meanwhile, poor quality engine oils have been shown to cause turbocharger bearing seizure in under 100 hours during a "heat soak" test.

Many engine oils will survive the 100 hour "heat soak" test, but... with considerable deposits and incipient oil passage blocking.  So what you select for your Duramax diesel oil is vital for long turbo life.  If you use typical or low-quality diesel oils, it is critical that you let the engine idle for a few minutes after use, to allow the engine and turbocharger to cool. This cool-down does not eliminate deposit formation when using petroleum diesel oils, but it can dramatically reduce it.

Take a look at the varnish deposits in this picture below. These are the results of a severe high temperature deposit test with some of the most trusted commercial brands. This test clearly shows that AMSOIL keeps engines cleaner longer than other major brands of diesel oils. Which oil would you rather have protecting your Duramax turbo-diesel engine?


The bottom line: To prevent or eliminate turbocharger bearing seizure, there is no substitute for a high quality synthetic diesel oil (like AMSOIL's) as they have been have been proven to maintain turbochargers in an almost "as fitted" condition, and significantly reduce deposit formation.

We are here to help you learn the facts and to show you how using superior AMSOIL products will increase the performance and add to the longevity of your Duramax Diesel, while saving you time and money. Duramax Diesel trucks are excellent vehicles and exceptionally well engineered by General Motors.  In our opinion, they are one of the most advanced vehicles ever produced.  However there are ways to make the performance and longevity even better with AMSOIL Synthetic Lubricants.


Skeptical? No problem.

Read our Q&A with hardcore "scamsoil skeptics"

Long life: We have an article describing an AMSOIL user with 731,000 miles on his 1993 Ford Aerostar, on the original engine and transmission. He was using AMSOIL from the beginning.  This type of mileage performance is unheard of in basic passenger vehicles with conventional petroleum oils, but is not uncommon when using AMSOIL synthetic lubricants.  However, newer Amsoil synthetic oil and filter technology have recently enabled the "million mile van" which is still running strong.   How much money was saved by not replacing those vans every 200,000 to 400,000 miles?


Improved Duramax fuel economy savings: 

My Duramax diesel truck gained 8% in fuel economy, and my car mpg improved 10%.  While most customers will only get a 5 to 10% fuel economy improvement, gains of 20% are not unheard of in some vehicles.  Phillip is a customer with a 1999 Oldsmobile Silhouette van who had changed his motor oil at 3,000 mile intervals.  In the spring of 2005 when he used Engine Flush and changed to AMSOIL engine oil with about 85,000 miles on the odometer, he got an instant 20% fuel economy increase which has been saving him about $12 per week.  That annual fuel savings of more than $600 is six times more than the $100 annual cost of the AMSOIL products. 


In a commercial fleet level, changing all drivetrain fluids to Amsoil usually averages a 5-10% fuel economy improvement.  This controlled study showed an 8.2% improvement, using older Amsoil fluid technologies.


Improve Your Fuel Economy: the Ultimate Guide




Biodiesel fuels produce more rapid breakdown of ANY engine oil. 
No matter what brand or type of engine oil you use, you will need to closely monitor your oil performance with oil analysis and shorten drain intervals as your use of biodiesel blends increases.  In many cases, this will mean cutting your previous oil drain intervals in half (assuming use of the same engine oil).  If extended oil drain intervals are not shortened or at least monitored with oil sampling, biodiesel contamination is likely to produce engine damage due to oil failure.  [MORE]



Which engine oil should you use
in your Duramax Diesel?


Your two choices for pre-2007 Duramax diesels are the 15W-40 Premium Heavy Duty Diesel & Marine oil (product AME), or the Series 3000 5W-30 Heavy Duty Diesel Motor Oil (product HDD).  For 2007 and later diesels, those models are equipped with the Diesel Particulate Filters (DPF's), and your truck requires Synthetic 5W-40 Premium Diesel Motor Oil (product DEO) which exceeds the new CJ-4 specification.

Download Free Diesel Oil Guide & Comparison

(1.3 mb pdf)


Despite your owner's manual recommendation of a 15W-40 oil, your Duramax engine - like nearly all engines - is designed to use a 30-weight oil.  The 15W-40 recommendation is based on the assumption of petroleum oils which will often "shear back" to a 30-weight oil in diesels, and if you use a 30-weight oil that shears back to a 20 weight oil you will have wear problems (or worse).  Of course, AMSOIL's HDD formulation will maintain viscosity as long as you are using it as recommended in a healthy engine (no fuel getting in the oil, for example) - so your engine will enjoy year-round benefit from the 30-weight oil it was designed for, including better fuel economy. 


Both the AME and HDD oils are 25,000 mile oils that outperform every other available diesel oil on the market, and are LESS EXPENSIVE to use because of those extended drain intervals.  Both oils are also superb performers in gasoline engines.  The DEO oil exceeds the performance of any other CJ-4 oil on the market.  Any of the three oils will work well for you, and they will all increase your Duramax fuel economy, but our best recommendation is for you to make an informed choice based on your specific needs.  Here are some suggestions to help you:


        For this Application...                                         Pick this oil:

  2007 & later models (CJ-4 spec is req'd)**                       5W-40 (DEO)

   Maximum Duramax Fuel Economy                           Series 3000 5W-30 (HDD)

    Cold Temperature Performance                             Series 3000 5W-30 (HDD)

    All-fleet oil for home/farm/garden                     5W-30 (HDD), or any of the three

            Lowest oil usage                                     15W-40 (AME) or 5W-40 (DEO)

          OTR Freight Hauling                           5W-30 (HDD), 5W-40 (DEO), 15W-40 (AME)*

       All-fleet oil for class 3-8                              15W-40 (AME) - or 5W-30 (HDD)**

All-purpose oil for logging/heavy-construction           15W-40 (AME), 5W-40 (DEO)*



*While it is difficult to compare them, Engineers generally believe the thicker 40-weight oils (AME & DEO) may provide slightly more wear protection than 5W-30 (HDD) in extremely heavy applications, particularly off-road/gravel where drivetrains can be subject to heavy torsional shock-loading.  However, for highway/city mileage, HDD fuel economy savings probably exceed savings from reduced wear with AME - if there is any measureable wear reduction at all with AME.  Experience has shown that changing to any of these three AMSOIL synthetic oils will produce fuel economy benefits for your Duramax.


**5W-40 (DEO) oil is also a fully backwards compatible, all-fleet oil.  So if using one oil for your entire fleet is one of your most important considerations, and your fleet includes 2007+ diesels (or earlier with DPF's), this is the oil to use.  However, be aware that the low TBN restrictions of the CJ-4 spec means that extended drain intervals will not be possible on your vehicles without oil sampling analysis.  (DEO has a TBN of 8.0, vs 12+ for AME & HDD.)  For this reason, our best recommendation is to use two fleet oils.  One for gas and 2006 or older diesels, and the other for 2007+ diesels.


Simply changing your oil more often with "reputable" oil will not give your Duramax all the benefits that AMSOIL offers:


You will not get improved fuel economy, you will not get reduced engine wear, you will not get reduced operating temperatures, you will not get extended drain intervals and you will not save money in the long run. Please, allow us to show you a better way. We are here to help you. You have everything to gain and absolutely nothing to lose!


Duramax Owners Questions and Answers
about lubrication, filtration and other truck maintenance issues:

These e-mailed/posted questions were answered by our degreed automotive engineers.
(None of them are employed by AMSOIL, Inc.)


Q:  Changing Fluids in my Duramax truck (January 2009, Posted on the TruckTrends forum)


I have a GMC Sierra 2500 HD Duramax 4x4 with a 6-speed standard gearbox.  I bought it new in 2001 and now have 98 000 miles on it.  Over the years I always made sure that the maintenance was done as per the owner manual but something bugs me.  Nowhere in the schedule maintenance does it talk about gearbox oil change.  They cover the engine oil, the engine coolant system and all kinds of minor items but they never talk about the standard transmission, the transfer case, the rear and front differentials, and what about the power steering and the hydraulic clutch?  How many years can we go without replacing the oil in all these components?  I understand that they use synthetic oil these days but are these synthetic oils good for the life of the truck?

A:  Recommendations for Changing Transmission Fluid, Transfer Case Lube, and Differential Gear Oil Fluid (Posted by us, 1/12/2009, we have made a few slight improvements below)

There's much more to this subject than meets the eye.  I stumbled across this question today while doing a search, and thought I could help clarify.  I'm a Mechanical Engineer with an '02 2500HD Duramax, and have spent the last decade in the automotive industry supplying to most of the OEM assembly plants.  I speak fairly regularly with an OEM GM engineer, who also has a Duramax, and we worked together in his shop installing remote bypass filter kits on our Duramax 6.6 engines.

For maximum vehicle life, OEM powertrain engineers (in general vehicle terms, rather than in Owner’s Manuals or Service Manuals) recommend changing ALL lubrication fluids in the first 2,000 to 4,000 miles of service.  This is generally because of the high operating temperatures and high wear-particle content generated during the break-in period, which break down and contaminate the lubricants.  Changing the fluid during this time, instead of at the factory-recommended intervals, can double to quadruple system life. Going to a high quality synthetic will at least double it again (NOT all of them are "factory fill" synthetics, as is often rumored).  For example, the front diff fill cap on 2500HD 4x4's through some 2004 models are not designed to have long-term compatibility with synthetics, which should tell you something about the factory fluid.  I forget which is which, but one is white, the other black.  You'll need to order the correct one to go synthetic up front.  

It goes back to "planned obsolescence". Current material finish and surface technologies allow slower wear, so that non-commercial users will make it past warranty with the factory drivetrain fluids, and commercial users will pay for diff and tranny failures that aren't covered under warranty for commercial use.
You can download a very interesting Research White Paper here on Gear Lubes - as far as I'm aware, the most authoritative testing ever published:  Gear Lube White Paper

If you note the background info in the first section you'll start to get a good idea of reality on differential failures, which also translates to tranny and transfer case failures: most of them fail, in truth, because their lubricants failed long ago. As as you'll see in the test data comparing those 14 gear lubes, just because it's "synthetic" doesn't mean it's high performance.

My Duramax purchase was a pivotal event for me because it sparked my shocked research to discover how easy it is to run 500k-1M miles as a 5th wheel tow vehicle... without drivetrain failures (I'm not going to vouch for injectors and fuel pumps, nor for offroading, etc.)  Many truck owners, like myself, plan to keep it for a very long time. If you're in that group, I recommend that you change everything to true synthetics, and don't use dealer fluids. Contrary to so many online forum postings around the web, the use of a dramatically superior synthetic lubricant is a dramatically superior choice that does NOT cause failures nor cause the OEM to deny warranty coverage, and the few Dealer service managers who claim otherwise are simply wrong - and wouldn't dare put their statements in writing.

And beware having a GM dealer change your transmission fluid: very few even carry a fluid that meets the Allison TES-295 spec.  I negotiated the fluid-exchange fee for bringing my own fluid to the Dealer.  Less than a mile from each other, my GM dealer didn't recommend using a synthetic in the Allison, while the commercial fleet center knew that Allison's extended commercial warranty required a high-performance synthetic - but still didn't carry it or use it.  It's eye-opening for a fleet to learn that Allison’s expensive extended warranty requires the expensive synthetic fluid, but that the fluid itself reduces tranny failures by way over 90%.  Hint - there are only two fluids that meet TES-295, and Allison lists only the one they’re partners with.

(Yeh, unfortunately very few people know this stuff… outside of lubrication, drivetrain, or reliability/maintenance engineers. Any vehicle can be a 500k+ mile vehicle, but it’s just not in the OEM’s or oil-drilling companies' best financial interests to explain how.  Hope this is helpful.)  

Brian - BSMET
Sierra 2500HD D/A
Diesel Turbo Life Saver
Amsoil Nanofiber Remote Bypass Filtration and over 60k miles since last oil change

[p.s. In early 2009, a new report was released which provides some details on a '99 Chevy Express 3500 van with the 5.7L gas engine, now over a million miles and still going strong on Amsoil. If a spark-plugged Chevy can do that, why not YOUR Duramax?]


I found your forum post on lubrication to be one of the most useful I have read. I downloaded the white paper you suggested and plan to study it. I am planning to purchase a GMC 2500HD for farm use in several months - to tow tractors and livestock. I have worked as a computer engineer at Sony, Hughes Aircraft and Walt Disney in the past. I would like to read anything you write about your truck or GMC experiences. Thanks for sharing this information! It is really hard to get good facts and reliable sources are so rare. So I really appreciate your efforts.

I have mostly owned Toyotas and had real good luck with them - vehicles and dealers. But the 5.7L Tundra does not have the tow capacity for larger utility tractors with trailer (4 ton and up for just tractor). I once owned the "Ford Explorer from hell" so cannot really imagine going through that run around again - ignition burned out on Mojave desert dirt road after 6 months, shift-on-the-fly did not work consistently the first 2 years until finally Ford installed a new larger spin up motor, door gaskets fell off for no reason, too much to list ... and dealing with Ford was an experience not to be believed. After much research the GMC 2500HD with Duramax and Allison trans seems the best choice. But I would love to hear any more thoughts you have on yours.

Ed from Taos, NM

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AMSOIL has been in business since 1972 and was the first company in the world to develop an API (American Petroleum Institute) rated synthetic lubricant for automotive applications. They coined the phrase "extended drain intervals" 30 years ago with 25,000 mile drain intervals, and ever since then they have been defining the leading edge of lubrication technology, innovation and performance.  No other company in the world offers 25,000 and 35,000 mile oil changes, and AMSOIL guarantees their product performance. No-one else does that. AMSOIL is the Gold Standard in lubrication and filtration, and amazingly, their superior-performance products are cheaper to use.  The fact is, if you’re not using AMSOIL lubricants and filters, you’re wasting money.


We are here to help you and are at your service to assist you in your advanced technology lubrication and filtration needs.  We hope you will allow us to show you a proven better way.  We have many satisfied customers using AMSOIL products in their commercial, trucking, and fleet vehicles, as well as personal, family and recreational vehicles. And now, you know the AMSOIL secret, too.  Welcome to the AMSOIL family.


AMSOIL is the undisputed leader in synthetics.............

Since 1972, AMSOIL Synthetic drivetrain LUBRICANTS have proven to be the highest performance engine oils, greases, transmission fluids, and hydraulic and differential gear oils on the market. 
But the other key issue is
nanofiber filtration. 
We now cover oil filters, air filters and other fluid filters like NO-ONE else can.  AMSOIL offers the highest performance, most cost-effective, most comprehensive filter line on earth.  Consider air and oil...


Until now, Nanofiber filtration technology has been used exclusively in heavy duty applications, including the US ARMY Abrams M1 tank. AMSOIL Ea Filters are the first and only filter line to bring this technology to the auto/light truck market.

EaO nanofiber oil filters provide unmatched full-flow filtering efficiency to 98.7 percent at 15 microns, and 50 percent at 7 microns.  This translates to a 70% reduction in engine wear rates, tripling remaining engine life while giving longer filter life and lower pressure drop for better cold-start performance: the only filtration that gives you the best performance in every category!  Compare that to the filters lining the auto-parts shelves, which don't tell you their common 7,500 mile design life and either won't tell you what micron level their efficiency rating is for, or they claim a micron particle size without stating an efficiency: deceptive, meaningless numbers. 

Additionally, consider bypass filtration systems for commercial and fleet applications in cars and light, medium and heavy trucks which can filter particles down to less than one micron and are 89% efficient at 1 micron, making oil changes virtually unnecessary and virtually eliminating engine wear.  (A standard full-flow oil filter can only filter to 20 microns with any reasonable efficiency, but 5-25 microns is widely accepted as the wear-particle size range.)  Easy to install, these oil filter systems have been proven by millions of miles of over-the road trucks, construction equipment and fleet service. And we use these on our personal diesel pickup trucks: my Duramax 2500HD has over 70,000 miles since the last oil drain, the oil analysis looks perfect, and the appearance of this diesel oil looks like a gas engine with 3,000 miles on the oil.

AIR FILTERS:Abrams M1A1 Battle Tank bites the dust with Nanofiber Filtration Technology

The MOST IMPORTANT filter on the M1A1 Abrams battle tank is its' nanofiber air filter. 
The MOST Important filter on YOUR vehicle is also the air filter.

It's far better, and easier, to keep wear particles out of the engine than it is to attempt filtering them out of the engine oil.  Yet filter companies and vehicle manufacturer's are strangely silent about actual air filter performance and engine needs.  Now AMSOIL offers world-leading breakthrough Ea air filters with exclusive nanofiber technology.  Based on battlefield-proven air-induction systems used in military ground and air vehicles, this high-technology filtration is now available for consumer use!  Ea filters are guaranteed for 4 years, 100,000 miles.  The engineering rule of thumb for damaging wear particle size is 5 to 25 microns.  Incredibly, these filters are 100% efficient at removing particles of 3 microns, and are 80% effective at removing particles of a 1 micron size.  This means that NO WEAR PARTICLES CAN GET PAST OUR Ea AIR FILTERS!  AND, they're less expensive to use than ANY other air filter.

For Power Sports applications, AMSOIL offers a line of oiled-foam filters.  These filters provide better performance than oiled-gauze air filters, and are used almost exclusively in most off-road applications including baja, dirt-track racing, and motocross.

For light to heavy trucks, both gas and diesel engines, AMSOIL's partnership with Donaldson provides you with the best performance and most cost-effective air filtration systems in the world.  These include both Powercore and Nanofiber technology filters.  We have the full line of  Donaldson Filters Now Available , including air, fuel, water, oil and hydraulic filters, with exclusive performance warranties (no one else in the industry offers filtration performance warranties).  Contact us for specific recommendations, or see our Diesel Page.

Air Induction Systems:

Well-engineered aftermarket air induction systems can provide airflow improvements with gains in horsepower, fuel economy, and towing torque.  Unfortunately in many cases they may also let far more wear particles into your engine than the OEM filter.  And oiled media can contaminate mass flow air sensors, causing problems with emissions, fuel economy and performance that can even damage transmissions in some cases.  AMSOIL lets you leave those problems behind. Their full line of nanofiber universal air induction filters (EaAU) are designed to replace stock oil wetted gauze or foam conical filters that were supplied with custom induction systems produced by K&N, Injen, S&B, Green, AIRAID, AFE, TrueFlow and more. Whether your air induction system is in a gasoline street-rod, or a diesel truck, you have great airflow but you need better filtration and more capacity than oiled gauze or foam.  AMSOIL Ea Air Induction Filters are dry no-oil filters with nanofiber filtration media to bring your aftermarket far better efficiency, 50 times the capacity, and excellent airflow while being easily cleanable - every 25,000 miles.


  • AMSOIL products saves you time and money.  With recommended extended drain intervals, AMSOIL performance typically costs LESS per year than conventional oil changes.

  • The only 25,000 mile/one-year and 35,000 mile/one-year motor oils in the world.

  • A vehicle lubrication solution with far less environmental impact, using an estimated 87% less oil and 5-10% less fuel !

  • The only oils and filters with a warranty for GUARANTEED performance!

  • Exceeds the most stringent performance specifications of all major U.S. and foreign automotive and truck manufacturers.

  • Provides up to four-times the wear protection of other motor oils.

  • Increases the mileage life of your vehicle.

  • Improves fuel economy.

  • Increases at-wheel horsepower.

  • Lowers transmission and differential operating temperatures and delivers better shifting, even in heavy towing.

  • Lowers fleet maintenance costs by lowering the costs of both scheduled maintenance, and mechanical repairs.

  • Lowers fleet capital costs by dramatically extending vehicle service-life.  (Vehicle mileage typically extended 20 to 100%.)

  • Diesel oil and filtration products designed to deliver more than 1,000,000 miles for over-the-road trucks before engine overhaul.

  • Used by many national racing teams, fleets, police departments, fire departments, ambulance fleets, construction firms and trucking companies.


DMT Technical operates as part of a group of highly skilled team of OEM Engineers and Lubrication and Filtration Specialists.  In fact, we are the ONLY such group on the internet, as well as the largest AND fastest-growing AMSOIL Dealer organization in the nation.  You too, can join our group when you become an AMSOIL Dealer and take advantage of all that we offer as you use products in your own vehicles or begin your own AMSOIL business. You cannot find a more knowledgeable and skilled group of Dealers anywhere. 

In addition, as a Dealer in our group you will receive exclusive unlimited product, technical and business support from the only group of Truck and Automotive Engineers and Lubrication Specialists on the net.  That's priceless - yet free - vital support that can make a huge difference to a growing business.

We do not run our business purely on the internet. We also have numerous commercial, industrial, trucking, excavating, construction, logging, police, racing and many more accounts that we support and service on a regular basis. We have several fully stocked warehouses and fully equipped shop facilities. This provides us with excellent knowledge of the products, equipment and the business and the ability to respond immediately to any of your needs. We will use this knowledge and experience to help you get started so you too can achieve your goals.

We possess the skills, desire and knowledge to answer questions, solve problems, improve efficiency, reduce downtime, maintenance costs and increase the durability and life of all of your vehicles.

Read what our satisfied customers have to say about us. Read through our website. Contact us with any questions. If you decide to become an AMSOIL Dealer you will be joining, in our opinion, the most skilled AMSOIL group there is. We will help you get started and provide you with the tools and information in order to be successful in this business or with technical and product assistance to use AMSOIL products in your own vehicles.

To get additional information:

We offer several options to receive information on AMSOIL. We welcome the opportunity to work with you personally as your servicing AMSOIL Dealer. Our AMSOIL Dealer Group is led by a Truck/Automotive Engineer and Lubrication Specialist with over 19 years experience. This exceptional benefit is unavailable elsewhere.

Please, email us at and we will send you an exclusive comprehensive package of product, technical and business information. If you are serious about AMS OIL products and the business opportunity this is the best option. You will receive extensive technical and business support from both myself and my Direct Jobber, a Detroit, Michigan Truck/Automotive Engineer and Lubrication Specialist with over 19 years experience. We look forward to helping you learn about AMSOIL.

Or for a smaller, very general information package (which includes a catalog and Dealer application) you can request information via any of the links below.  Please note that your information is always held in confidence per our Privacy Policy, and will never be sold, loaned or otherwise distributed.

To request a FREE Factory Direct Catalog by MAIL

To Immediately Download a FREE Factory Direct Catalog

For Information on Becoming an AMSOIL Dealer

To Buy AMSOIL Products in the AMSOIL On-Line Store

To Sell AMSOIL in Your Store or Purchase For Use in Your Businesses Equipment

To visit the AMSOIL Corporate Website for Product and Business Opportunity Information


AMSOIL is Proudly Made in the U.S.A.

AMSOIL is owned by Americans.

AMSOIL is America's Oil.

Filtration and Lubrication Gold Standards - the Best

DMT Technical

Ultimate Synthetic Oil - AMSOIL Products

Garner, North Carolina  27529

Phone: (419) 630-0874

E-mail: Brian