75W90 Gear Oil

Specifically Engineered for 500,000-Mile Service Life in Over-the-Road Trucks

AMSOIL 75W90 Gear Oil is a synthetic long-life gear oil engineered for extended drain intervals up to 500,000 miles as set by equipment manufacturers for over-the-road trucks and heavy equipment. Provides long life in passenger cars and trucks. Excellent all-season summer and winter performance. Outperforms all conventional gear oils.

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75W90 Gear Oil engineered by AMSOIL is an extended-drain gear lube engineered to last several times longer and protect gears better than conventional gear oils. This exclusive AMSOIL formulation of premium synthetic base oils and high-performance additives resists acid, carbon, and varnish formation from oxidative breakdown. Components run cleaner and last longer. AMSOIL Long-Life Synthetic Gear Oil is shear-stable and reduces friction. It maintains its viscosity during extended service for maximum wear control and is fuel-efficient. The superior cold-temperature fluidity and high-temperature stability properties of AMSOIL 75W90 Gear Oil make it excellent for all-season use. AMSOIL Long Life Synthetic Gear Oil helps extend equipment life and reduce maintenance costs.

AMSOIL Long Life Synthetic Gear Lube, in the correct viscosity grade, is recommended for domestic and foreign applications, including over-the-road trucks, light-, medium- and heavy-duty trucks, off-road equipment, commercial vehicles, motor homes, autos, SUVs, emergency vehicles, buses, delivery/utility vehicles, and tractors.

Use AMSOIL Long Life Synthetic Gear Lube in differentials, manual transmissions, or other gear applications where one or more of the following standards are specified: API GL-5 & MT-1, MIL-PRF-2105E, Dana* SHAES* 234 (Formerly Eaton* PS-037) for 250,000 miles, Dana SHAES 256 (Formerly Eaton PS-163) for 500,000 miles, Dana SHAES 429A, Mack* GO-J & GO-J+, Meritor* 0-76N (75W-90) & 0-80 (80W-140) plus hypoid gear oil specifications from ZF TE-ML 07A and 08 foreign and domestic manufacturers such as GM*, Ford* and Daimler* Chrysler*. It can also be used in rear axles where API Service GL-4 lubricant is recommended.

AMSOIL Long Life Synthetic 75W90 Gear Oil provides:

  • High Load gear and bearing protection
  • Protection from rust and corrosion
  • Better cold-weather shifting
  • Improved efficiency
  • Improved seal life

For product service life in differentials, consult your owner’s manual or the Original Equipment Manufacturer (OEM) to establish the application, NORMAL or SEVERE.

Normal Service Severe Service
Cars, SUVs, Light Trucks Drain at 100,000 miles of service or according to the owner’s manual, whichever is longer Drain at 50,000 miles of service or according to the owner’s manual, whichever is longer
Heavy-Duty Class 8 Line Haul Follow the OEM drain interval (miles or hours) for synthetic oil up to 500,000 miles or three years, whichever comes first.
Vocational/Delivery Follow the OEM drain interval (miles or hours) for synthetic oil up to 120,000 miles or three years, whichever comes first.
Heavy Duty Off-Road Follow the OEM drain interval (miles or hours) for synthetic oil up to 100,000 miles or two years, whichever comes first.


For product service life in non-differential applications, consult the owner’s manual or the OEM for either normal or severe synthetic oil service intervals. Where service intervals are unavailable, drain at twice the interval for conventional oil.

Note: AMSOIL does not support extended drain intervals where water contamination occurs. Check and service the gear oil frequently when water contamination is possible.

Gear oils should be changed more frequently when operating vehicles or equipment in dusty or dirty conditions unless the gear system is properly sealed and equipped with membrane-type breathers.

AMSOIL Long-Life Synthetic Gear Lube is compatible with conventional gear oil. Mixing AMSOIL gear oils with other oil, however, reduces the oil’s benefits and nullifies the extended service life recommendations.

AMSOIL Long-Life Synthetic Gear Oil is compatible with most limited-slip differentials. If limited-slip differential chatter occurs, add AMSOIL Slip-Lock® friction modifier additive.

AMSOIL Long Life Synthetic Gear Lube 75W-90 replaces competitors’ 75W-90 and 80W-90 viscosity grades. AMSOIL Long Life Synthetic Gear Lube 80W-140 replaces competitors’ 80W-140 and 85W-140 viscosity grades.

AMSOIL products are backed by a Limited Liability Warranty. For complete information visit www.amsoil.com/warranty/.

This product is not expected to cause health concerns when used for the intended applications and according to the recommendations in the Safety Data Sheet (SDS). An SDS is available online at www.amsoil.com or upon request at (715) 392-7101. Keep Out of Reach of Children. Recycle used oil and bottle.

* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

Technical Specifications


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Data Bulletins

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