AMSOIL 75W-90 100% SYNTHETIC MARINE GEAR LUBE

AMSOIL 75W-90 100% Synthetic Marine Gear Lube is a purpose-built lower unit lubricant that delivers exceptional gear and bearing protection in outboard, sterndrive, and marine transmission applications, even when water intrusion compromises the oil.

Lower unit gear cases operate in a uniquely hostile environment. Seals age, prop shaft seals take hits from fishing line and debris, and water finds its way in. Once water contaminates conventional gear lube, extreme-pressure protection drops, foam forms, rust takes hold, and gear wear accelerates. High-horsepower outboards and fast-accelerating boats compound the problem by generating severe shock loads through propeller cavitation. A gear lube designed for automotive use simply is not formulated for these conditions.

GEAR AND BEARING PROTECTION WITH UP TO 15% WATER CONTAMINATION
Water contamination is not a question of "if" in marine lower units. It is a question of "when" and "how much." AMSOIL Synthetic Marine Gear Lube maintains a Falex Extreme-Pressure Load of 2,000 LbF (ASTM D3233B) both dry and with 15% water contamination. That means the extreme-pressure film strength does not degrade when water enters the lower unit. For Mercury, Yamaha, Suzuki, Honda, and Evinrude outboard owners running high-horsepower motors, this level of protection directly addresses the gear pitting and bearing failure that result from water-compromised lubricants.

ZERO FOAM IN ALL THREE ASTM SEQUENCES
Foam in a gear lube disrupts the oil film between gear teeth and bearing surfaces. Water contamination dramatically increases foaming tendency in most lubricants. AMSOIL Synthetic Marine Gear Lube produces zero foam across all three sequences of ASTM D892 testing, both in new condition and when contaminated with 15% water. Zero foam means uninterrupted film strength, which translates directly to reduced wear and consistent power transfer through the lower unit.

RUST AND CORROSION PREVENTION
Saltwater boaters know corrosion never stops working. AMSOIL Synthetic Marine Gear Lube is formulated to prevent rust formation on gears, bearings, and shafts, and it is compatible with aluminum, copper, and brass alloys found throughout marine lower units and sterndrives. This matters whether the boat sits on a trailer between weekend trips or stays in a wet slip for weeks at a time.

EXTENDED SEAL LIFE
Dried-out, hardened seals are the primary pathway for water intrusion into lower units. AMSOIL Synthetic Marine Gear Lube is formulated to keep seals pliable and functional over time, reducing the likelihood of water contamination in the first place. This is especially relevant for boats stored over winter or used infrequently, where seal degradation between uses can go unnoticed until milky oil appears at the next drain.

SHOCK LOAD PROTECTION FOR HIGH-HORSEPOWER APPLICATIONS
Propeller cavitation during hard acceleration, tight turns, or rough water creates sudden, violent load spikes on lower unit gears. AMSOIL Synthetic Marine Gear Lube is fortified with extreme-pressure additives specifically to handle these shock loads. Boats running 150hp, 250hp, or 300hp-plus outboards from Mercury, Yamaha, or Suzuki generate significant cavitation forces that demand a gear lube built for the application.

SPECIFICATIONS AND COMPATIBILITY
AMSOIL 75W-90 Synthetic Marine Gear Lube meets API GL-4 and GL-5 specifications. It is suitable for fresh- and saltwater applications requiring 75W-90 or 80W-90 gear lube. Compatible applications include lower units made by Mercury/Mariner, Johnson/Evinrude, Bombardier, Honda, Yamaha, Suzuki, Force/US Marine, Nissan, Tohatsu, and Harbormaster. It also covers sterndrives from MerCruiser-Bravo, OMC/Bombardier, Volvo-Penta, Yanmar, Konrad, and Marine Drive Systems, V-drives from Casale & Menkins, bow thrusters from Harbormaster Marine, and transmissions from ZF Marine Transmission. It is compatible with other synthetic and conventional marine gear lubes and is backed by the AMSOIL Limited Warranty.

SERVICE LIFE
Follow manufacturer-recommended service intervals. It is generally good practice to change lower unit gear lube at the end of each season prior to storage to remove any accumulated water and protect internal components during the off-season.