Chevy/GMC Duramax Diesel Engines

The best diesel oil and my first recommendations are to change your oil to the AMSOIL 15W-40 Synthetic Heavy Duty Diesel Oil Part #AME-1G CASE (4 gallons). Cases of quarts or 5 gallons are also available. The Series 3000 5W-30 Synthetic Heavy Duty Diesel oil is also an excellent choice and is a more fuel efficient type of diesel oil if you accumulate most of your miles on the highway. Change the oil at 25,000-mile/1-year drain intervals unless you are using by-pass filtration and oil analysis testing in order to go beyond 25,000 miles/1-year change intervals. Use the AMSOIL EaO-52 (EA-1 Filter) Absolute Efficiency Oil Filter changed at 25,000-mile/1-year intervals ($13.15 wholesale vs. $17.30 retail). These are the only 25,000-mile/1-year oil filters on the market.

Please note that 2007 (and newer) engines with an EGR system and (DPF) Diesel Particulate Filter on the exhaust system must use the AMSOIL Synthetic 5W-40 Premium API CJ-4 Diesel Oil (Product Code: DEO). The oil change interval is recommended for the longest service interval established by the engine, vehicle or equipment manufacturer. Drain intervals may be extended based on oil analysis.

Use the AMSOIL's Absolute Efficiency EaA123 Air Filter (up to 2005). This filter is specified and guaranteed for 4 years or 100,000 miles. It utilizes nanofiber technology that absolutely no other company offers except AMSOIL. It outflows, stops more dirt and outperforms every other oil filter on the market. We also offer Powercore Air Filters for newer models. Please email me for part #’s and pricing.

Use the Torque Drive Synthetic Automatic Transmission Fluid. The Torque Drive ATF is engineered for the Allison Transmission in the Duramax. It is an exact replacement for Transynd (the factory fill ATF) and is also a TES 295 specification fluid. Torque drive comes in quarts, gallons, cases of quarts and gallons, 2.5 gallon and 5 gallon sizes. Your warranty is still valid with AMSOIL Torque Drive as it meets and exceeds all GM and Allison specifications and is approved for use by Allison. Change intervals are 50,000 miles or 24 months for severe service or 100,000 miles or 48 months in vehicles used for general use.

Use the Severe Gear 75W-90 Synthetic Gear Lube in the front and rear axle. You will need around 8 quarts to do both the front and rear. If you have a limited slip differential, in most cases, you will not need to add AMSOIL Slip-Lock friction modifier. In some rare cases, if you do hear chatter on turns, then you will need to install a bottle of friction modifier available from your Chevrolet dealer. AMSOIL also offers a severe gear 75W-140 Gear Lube for extreme severe duty applications, such as heavy towing with your Duramax.

The 75W-90 is recommended by many manufacturers because it is more fuel efficient than a 75W-140. Ford uses 75W-140 synthetic in the rear axles of all production trucks. Chevrolet prefers 75W-90 mainly due to fuel economy concerns for CAFE. I personally recommend the 75W-140 because during extensive severe durability testing performed by Ford and Dana, the 75W-140 outperformed the 75W-90. That does not mean the 75W-90 is not good to use, just that the 75W-140 is better under certain severe duty conditions. Also, most front differentials recommend 75W-90 or 80W-90 because the front axle is typically not used very much so they can get by with a lower cost oil. The axles in the Duramax are manufactured by American Axle Manufacturing and are a 3.73:1 ratio and feature an Eaton G80 mechanical locker.

AMSOIL Diesel Concentrate Performance Fuel Additive
AMSOIL Diesel Concentrate (ADF) provides maximum diesel operating efficiency. It compensates for the variances in quality of different fuels (including biodiesel) and the deficiencies of today’s Ultra Low Sulfur Diesel fuel (ULSD) for better engine operation. New engine technology, tighter tolerances and emissions regulations require high quality diesel fuel for long-term engine operatibility. AMSOIL Diesel Concentrate improves diesel fuel quality to exceed today’s stringent performance requirements. AMSOIL Diesel Concentrate extends equipment life, lowers operating costs and improves diesel performance. AMSOIL Diesel Concentrate provides the following benefits:

  • Improves Fuel Economy and Restores Horsepower
  • Lubricates Fuel Pump and Injectors: ULSD has significantly reduced lubricity – a critical property in controlling wear in fuel pumps and injectors. AMSOIL Diesel Concentrate adds back in all the lubricity properties needed and more.
  • Reduces Cylinder wear. Retains Engine Oil TBN Longer
  • Minimizes Soot Loading
  • Stabilizes Fuel
  • Improves Water Tolerance

Use one ounce of AMSOIL Diesel Concentrate to five gallons of fuel.

High fuel prices are increasing operating costs for everyone. AMSOIL Diesel Concentrate has proven in industry standard tests to improve fuel economy in used diesel engines by up to five percent. At $3.00 per gallon for diesel fuel, even a modest three percent improvement in fuel economy equals a savings of $0.09 per gallon. With a treat rate of one oz. of AMSOIL Diesel Concentrate to five gallons of fuel, at U.S. Preferred Customer/Dealer prices the net treat cost of AMSOIL ADF is $0.06 per gallon, bringing the total savings to $0.03 per gallon and negating the cost of AMSOIL Diesel Concentrate altogether.

AMSOIL Diesel Cold Flow Improver

Combining AMSOIL Diesel Concentrate with a cold flow improvement property is not cost effective in the summer months, or to AMSOIL customers who live in the south. To keep costs down for Dealers and customers, AMSOIL Diesel Concentrate no longer includes a cold flow improver. Instead, AMSOIL provides new AMSOIL Diesel Cold Flow Improver (DFF) for low-temperature applications below 40°F. Recommended mix ratio is one ounce of additive per five gallons of fuel. AMSOIL Cetane Boost will raise cetane levels up to 7 points for improved performance and fuel economy

This should get you started. Do not become overwhelmed by all there is to do. Just do a little bit at a time and eventually you will have everything converted over. Once you do, you will have a better performing and protected truck. Please contact me if you have any questions. I am here to assist you in using the very best AMSOIL Synthetic Lubricants and Filtration Systems for your vehicle.


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