Hypoid Gear Oil

Hypoid Gear Oil—What is It?

A hypoid gear is a type of spiral bevel gear found in axle differentials and used to transfer power to the axle shafts from the driveline. Hypoid gears engage the pinion under the centerline of the ring gear, which drops the driveshaft away from the vehicle’s underside.

Hypoid gear oil is specially formulated with extreme pressure additives to be able to work ideally with and protect hypoid gears. AMSOIL SEVERE GEAR Synthetic Gear Lube provides exceptional hypoid gear protection.

Can You Mix Synthetic Gear Oil with Regular?

Usually yes. Synthetic and conventional gear oils are typically compatible, but it is possible that mixing the two can impact the life expectancy of the oil’s life and decrease its benefits. AMSOIL doesn’t support extended drain intervals with mixed oils.

Can You Mix Conventional and Synthetic Oil?

It is technically safe since they’re compatible, but it’s not the wisest idea. Learn why.

Can You Use Conventional Gear Oil in a Marine Lower Unit?

So long as it meets the requirements listed in the owner’s manual, yes. However, it’s best practice to use a gear oil that is specifically made for marine lower unit applications. Marine lower units come into contact with water on a regular basis, and gear oil water contamination increases its chances of foaming, which disturbs the oil film and can lead to wear. An oil formulated specifically for marine gear is resistant to foaming and can provide reliable performance when subject to contamination from water.

AMSOIL Synthetic Marine Gear Lube fights foaming and provides exceptional protection against loss of power and wear on gears, even with 15% water contamination.

What Weight & Type of Gear Oil Should I Use?

For the ultimate protection and top performance, please reference your owner’s manual to see what the manufacturer recommends. You’ll also find information for your particular application: viscosity (75W-90, 75W-140, etc.) and specification (API GL-4, API GL-5, API MT-1, etc.). Nearly all hypoid gear sets will need GL-5 because of its requirement for protection from extreme pressure.

How Often Should Gear Oil Be Changed?

Please reference your owner’s manual or the original equipment manufacturer (OEM) to determine whether your situation is considered normal or severe—and follow the appropriate steps. AMSOIL synthetic gear lubes also offer both regular and severe service-drain interval recommendations and the option to save money and time with extended drain intervals. 

So What’s the Best Oil for my Differential?

AMSOIL SEVERE GEAR Synthetic Gear Lube tops its competitors when it comes to protecting bearings and gears from severe service. By its very nature, SEVERE GEAR synthetic gear lube fights high-heat breakdown, resisting acids and metal-to-metal contact through a barrier. The wax-free construction also develops cold-flow properties, which increases fuel economy and performance in colder weather. More benefits of SEVERE GEAR include:

  • Exceptional film strength
  • Thermal runaway control
  • Rust and corrosion defense
  • Lower operating temperatures
  • Maximized efficiency
  • A longer life for oil, equipment & seal
  • Flexible packaging, allowing for a fast and mess-free installation