Gear oil Vs Engine oil | In-Depth Comparison | Comparison Chart

Gear oil and engine oil are not transmission fluids. These two oils are used for vehicle gear and engines. Gear oil is designed for the vehicle gearbox, and engine oil is designed to protect the engine and make the engine long-life. This is the main concept of these two oils.

To compare gear oil Vs engine oil, you have to know some myths. To maintain the vehicle regularly, you have to consider the right oil for your vehicle. You can’t consider multiple oil systems for your vehicle, but you can choose the right one to make your vehicle longer-life.

Gear oil Vs Engine oil

Gear oil Vs Engine oil

One of the most important ways to keep your vehicle engine in good condition is to check your engine oil regularly. Older vehicles, especially cars, need to change the oil after 3000-mile drives.

The standard transmission trucks and cars require additional gear oil, which you have to provide regularly. You have to be careful that you apply debris-free gear oil or lubricant.

So, what is the difference between these two oils, or which one is better for you? It is easier to answer like yes or no by providing a detailed answer.

Gear Oil & Engine Oil Core Differences

  • Protection

The main goals of gear oil and engine oils are to provide your vehicle engines and maximum gearbox protection from corrosion and rust. Gear oil must prevent rust and corrosion from vehicle material.

On the other hand, engine oil is ready to protect the vehicle’s engine from rust and corrosion. But rust and corrosion are not ready nearly as prevents the vehicle engine when you are using engine oil.

  • Fluid additives

Undoubtedly, both of the oils come with enough fluid additives. They have minimum extreme pressure and anti-wear agents. But, if we need to compare these two oils by fluid additives, gear oil is ready to reduce more pressure and anti-wear agents than engine oil.

Read About: AGMA 5 EP Gear Oil

On the contrary, viscosity is another factor of these two oils. It is difficult to make a difference between these two oils of viscosity. However, gear oil comes with a higher viscosity than engine oil.

According to the Society of Automotive Engineers (SAE), Gear oil comes with a higher viscosity than engine oil. They also provide different grade scales, indicating that the Gear oil has much more viscosity than engine oil.

  • Designs of Engine Oil & Gear Oil

Engine oil is designed for high run temperatures. Similarly, gear oil is designed for high-pressure movement. On the other hand, high-quality gear oil is not only lubricant but also removes debris and cools.

Gear oil and engine oil are both anti-wear fluid additives. To compare these two oils by anti-wear fluid additives, gear oil is subject to provide better performance of anti-wear fluid additives.

  • Shock-Loading

Gear oil’s high viscosity and extreme pressure formulation are ready to provide noise-free performance. You will discover minimum noise from your vehicle when you use Gear oil.

Moreover, motor oil is also ready to reduce annoying noise, unlike Gear oil. In dissipating shock-loading, gear oil is far better because of its formulation and viscosity.

Comparison Chart of Gear Oil Vs Engine Oil

Gear OilEngine Oil
Gear oil deals with extreme pressure and comes with high viscosityEngine oil deals with high run temperatures. It also has enough viscosity but not more than Gear oil.
Anti-foam agents are widely applied to this oil and work against dust or water contamination.Engine oil is also ready to avoid contamination by dust or water but is not strong as Gear oil.
The Gear oil ingredients have friction, glycerol, and/or polyglycerolThe ingredients of engine oil are base oil, detergent, dispersant, etc.
Gear oil has to be changed after 100,000 km intervalEngine oils have to be changed after 10,000 to 15,000 km interval

Gear Oil Vs Hydraulic Oil

Hydraulic oil and Gear oil differ because of their high viscosity and thicker design. Gear oil is always a better solution to get high viscosity and thicker benefits than Hydraulic oil.

In addition, Gear oil is used for cars, and when you use this oil, it acts like a lubricant. On the other hand, Hydraulic oil is ready to help move like water-powered apparatus and the vehicles’ hardware.

Hydraulic oil is designed to transfer power to the hydraulic system thoroughly. For example, hydraulic oil works for hydraulic brakes, lift power steering systems, and others.

Read: Gear Oil Vs Transmission Oil

Is Gear Oil the Same As Transmission Fluid?

No, they are not similar because of their chemical composition. Moreover, they target different types of transmission fluid.

Undoubtedly, gear oil is a lubricant that is also manual transmission. It is used for semi-trucks and light-duty vehicles. Though they have different chemical compositions, their function and goals are similar. So, it is clear that gear oil and transmission fluid is similar in their functions and goals but different in chemical composition.

Read: Semi Truck Transmission Oil Change

Is Transmission Oil and Engine Oil the Same?

Engine oil and transmission oil differ from each other. You may know that engine is the lubricant and the transmission fluid is hydraulic. Though they are different oils, you will still find lots of similarities between these oils.

Transmission oil is ready to supply power to the hydraulic part of the vehicle as well as the transmission. Similarly, engine oil is used for engine lubricant, and you can’t use it for the hydraulic part of the vehicle.

According to role plays, both of these oils are different from each other. These are the visible difference that makes them differ from each other.

Related: Can You Mix Gearbox Oil?

Is Transmission Oil and Engine Oil the Same?

FAQs (Frequently Ask Questions)

Q: Where to put gear oil in a car?

Answer: To put gear oil in your car, you have to find out the location. However, located in the back of the engine compartment. It is pretty easy to find. At this location, you can put gear oil in your car. If you still need to find the location, you can check out the owner’s manual to hassle-free find out the location.

Q: Can gear oil be used as engine oil?

Answer: Gear oil and engine oil are two different types of oil, and their ingredients are also different. Gear oil is designed for extreme pressure, and engine oil is designed for temperature and protect the engine. The viscosity is also different, and that’s why you should not mix gear oil with engine oil or use gear oil instead of engine oil. It will damage your vehicle engine slowly or within a very short time.

Q: What is the difference between engine oil and gear oil?

Answer: Engine oil and gear oil have some visible differences. First of all, their ingredients are different. Secondly, these two oils are used for various purposes, such as gear oil used for the gearbox and engine oil used to reduce temperature and protect the engine from rust, corrosion, and other harmful elements.

Q: When do I replace both?

Answer: You should not replace both of these oils, Gear, and engine. Because when you mix them, it may damage your vehicle engine and create other problems. However, you can add some Gear oil on the engine oil when it comes with lower viscosity, and engine oil comes with higher viscosity. Note you have to do it very carefully. If possible, take help from an expert person.

Final Verdict!

Engine oil and Gear oil are two different oils, and they are used for different purposes. They have many differences, such as ingredients, designs, performance, viscosity, foam, fluid additives, etc. These two oils are undoubtedly popular, and you must know which is better for your vehicle.

Gear oil comes with high viscosity, can reduce extreme pressure, and helps the gearbox run smoothly. Motor oil is designed for the vehicle’s motor to reduce temperature, protect the engine from wear, and so on.



Emon is Lubricants specialist who studied on Petroleum Engineering in UAE. He have more than 10 years experience on different kinds of lubrication including automobile troubleshooting.