Marine 75W-90 (AGM)

Amsoil Synthetic Marine Gear Lube 75W-90 (AGM)
Data Bulletin 

Product Highlights

True marine gear performance. Provides superior protection from shock loading. Resists foam and retains extreme-pressure qualities even when subjected to 10% water contamination. For use in outboard lower units, sterndrives, V-drives, bow and tunnel thrusters and marine transmissions Excellent for use in ATVs.

AMSOIL Synthetic Marine Gear Lube is an exclusive AMSOIL formulation of synthetic base oils and high-performance additives that addresses the specific concerns of marine applications. It is fortified with extreme-pressure (EP) additives for superior protection of fast-accelerating, high-torque/horsepower engines. It protects against shock loading from cavitation of heavily loaded engines.

AMSOIL Synthetic Marine Gear Lube is water resistant. It maintains extreme-pressure protection even when contaminated with as much as 10 percent water. It promotes longer seal life to help prevent water contamination. AMSOIL Synthetic Marine Gear Lube is designed to prevent rust and is compatible with aluminum, copper and brass alloys.

Package Sizes (AGM)

Code Sizes Units
AGMQT (AGMQT-EA) 1-Quart Bottle Each
AGMQT (AGMQT-CA) 1-Quart Bottle Case of 12
AGM1G (AGM1G-EA) 1-Gallon Each
AGM1G (AGM1G-CA) 1-Gallon Case of 4
AGMTB (AGMTB-EA) 10-Ounce Tube Each
AGMTB (AGMTB-CA) 10-Ounce Tube Case of 6
AGM05 (AGM05-EA) 5-Gallon Pail Each
AGM16 (AGM16-EA) 16-Gallon Keg Each
AGM30 (AGM30-EA) 30-Gallon Drum Each
AGM55 (AGM55-EA) 55-Gallon Drum Each
AGM27 (AGM27-EA) 275-Gallon Tote Each


Use in fresh- and saltwater applications that require 75W-90 or 75W-90 gear lube and any of the specifications listed below, including lower units made by Mercury/Mariner*, Johnson/Evinrude*, Bombardier*, Honda*, Yamaha*, Suzuki*, Force/US Marine*, Nissan*, Tohatsu* and Harbormaster*; sterndrives made by Mercruiser-Bravo*, OMC/Bombardier, Volvo-Penta*, Yanmar*, Konrad* and Marine Drive Systems*; V-drives made by Casale & Menkins*; bow thrusters made by Harbormaster Marine*; and transmissions made by ZF Marine Transmission*.

  • API GL-4, GL-5

Marine gear oils operate in environments subject to water contamination. The chart above demonstrates the ability of AMSOIL Synthetic Marine Gear Lube to maintain designed qualities such as extreme-pressure/anti-wear performance and resistance to foaming, even when subjected to 10 percent water contamination.

The Falex Procedure is a measurement of a gear lube’s extreme-pressure and anti-wear properties. A high value in the Falex Extreme-Pressure Test relates to extra extreme-pressure protection. AMSOIL Synthetic Marine Gear Lube provides extreme-pressure protection and is highly resistant to the effects of water contamination.

The presence of foam in a lubricant disrupts the oil film and promotes wear. Water contamination can increase the likelihood of foaming. Industry-standard testing demonstrates zero foam in both new and water-contaminated AMSOIL Synthetic Marine Gear Lube.

Amsoil Synthetic Marine Gear Lube 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.

For product service life in non-differential applications, consult 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.


AMSOIL Synthetic Marine Gear Lube is compatible with other commercially available conventional and synthetic marine gear lubes.

Follow manufacturers’ recommended service intervals.

It is generally a good idea to change gear lube at the end of a season prior to storage.

Amsoil Product Warranty

Amsoil products are backed by a Limited Liability Warranty. For complete information visit

Amsoil Synthetic Marine Gear Lube 75W-90 (AGM)
Kinematic Viscosity @ 100˚C, cSt (ASTM D445) 15.4
Kinematic Viscosity @ 40˚C, cSt (ASTM D445) 117.3
Viscosity Index (ASTM D2270) 137
Pour Point ˚C (˚F) (ASTM D97) -43 (-45)
Flash Point ˚C (˚F) (ASTM D92) 208 (406)
Brookfield Viscosity @ -40˚C, cP (ASTM D2983) 46,200
Foam Stability (ASTM D892) 0/0, 0/0, 0/0
Copper Corrosion 3 hr, 121˚C (ASTM D130) 1B
Falex Procedure B (ASTM D3233) (failure load, lbf.) 2000
Four-Ball Wear Test (ASTM D4172 @40kg, 75°, 1200 rpm, 1hr), Scar, mm) 0.43

*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.

Leave a Reply

Your email address will not be published. Required fields are marked *