Gear oils are used for reducing speeds and boosting torque. They are quite compact and can achieve very high-speed rations, often 60:1 or higher. This article will help you understand the essentials of gear oil lubrication.


When choosing gear oils, there are many factors like the projected life of a gearbox, its seals, and the performance of the gearbox. Usually, end-users rely on their OEMs to identify the best fear oil, so OEMs need to value it as a machine element much similarly that they value hardness of the fears, bearing, materials, and so on.

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Different types of oils have different functions and characteristics.

  • The Extreme Pressure (EP) gear oil. 
    • It is multi-grade. It is much better to use it in the gearboxes that run under a great deal of pressure. Generally, it is designed as synthetic or mineral bases.
  • The synthetic gear oil.
    • It stops rust, foaming, inside the gearbox, and wear of the gears. This gearbox oil can be performed at extremely high or low temperatures.
  • The rust-preventing gear oil.
    • This gearbox oil is best utilized in low-load gearboxes. It can be future divided into mono-grade and also multi-grade gear oil.


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How To Replace Outboard Gear Oil

  • With the outboard motor still up, loosen both drain screws. It is simpler to loosen the bottom screw with the outboard tilted up.
  • Tilt the outboard down as far as you can. If the prop shaft can not be horizontal or angling down, you will require to drop the front of the trailer or jack the back of the trailer.
  • Remove outboard drain screws and drain oil into a container. There will be two screws at the bottom and top of the gearbox.
  • Inspect old gear oil for signs of metal or water contamination. Examine these magnets for signs the oil in the sun, metal, fillings will be shiny in the sunlight. Water will either drain out first before the oil. 
  • Before filling the gearbox ensure both of the old grain screw washers have been removed and all of the pieces are cleaned. 
  • Fit a new seal to each drain screw.
  • Fill the gearbox with outboard motor gear oil only.
  • Fill the gearbox from the bottom opening you can buy gear oil a bottle of gear oil and a pump from Phillips 66.
  • Pump the oil until it comes out of the top opening, wait a couple of minutes to let any air bubbles work.
  • Fit the drain plug screw into the top hole first and tighten it safely. 
  • Remove the pump from the bottom hole and fit the drain screw and tighten securely.
  • Clean any excess oil and you are all done!


One important note is to make sure you purchase the correct seal or washer for your make of outboard.