Difference Between Gear Oil and Engine Oil

Published: 3 Jul 2025

Gear oil and engine oil are both essential for keeping your vehicle running smoothly, but they serve different purposes. Knowing the difference between gear oil and engine oil can help you take better care of your car and avoid costly repairs.

Engine Oil

It is used in the engine. It helps the engine parts move easily and stay cool.
It is thin, so it moves fast inside the engine.
It includes detergents that help keep the engine clean, along with additives that reduce friction and protect against rust and corrosion.
It is not too thick and has a light smell.
It is used inside engines.
It works at extreme temperatures and hot parts. It must endure strong, high heat.
It also helps reduce engine noise by lubricating moving parts.
It usually needs changing every 5,000 to 10,000 kilometers because it gets dirty faster.
It helps remove dirt and sludge from the engine.
It lubricates parts that move very fast but with less pressure.

Gear Oil

It is used in the gearbox. It helps gears move smoothly and stay safe.
It is thicker than engine oil. Thick oil provides greater protection.
It has strong chemicals that protect the gears under heavy pressure.
It has a strong smell. It looks dark and thick.
It is used in parts like the gearbox, differentials, and other gear systems
It works in parts that take heavy loads, but not as much heat.
Gear oil reduces the noise generated by the gears, making them run smoothly and quietly.
It lasts longer, often 40,000 to 100,000 km.
It has special Extreme Pressure (EP) additives that protect the gears when they press hard against each other.
It doesn’t clean; it only protects gears from wear and tear.
It lubricates parts that move more slowly but under heavy pressure.

Conclusion

In short, engine oil is made for the engine, and gear oil is made for gear systems like the transmission and differential. Using the correct oil in the right place helps your car run better and last longer. Check your manual or talk to a mechanic if you’re not sure which oil to use.