Engine Oil vs. Gear Oil

Engine Oil vs. Gear Oil? A Step by Step Guide

After using your vehicle for a long time, you have to change the oil or use oil to make the engine and other parts run because car parts move at an incredible number of repetitions per minute.

Gear oil is designed specifically for use on gears. It is a liquid lubricant that aids in the smooth operation of gearbox units. The lubricant contains oxidizing compounds and has a high viscosity.

Engine oil, often known as motor oil, is used to lubricate the internal combustion engine’s internal components. It keeps the internal units cool while in use and protects them from corrosion.

Engine oil and gear oil differs in terms of their properties. The functions and use of both oil are different and these cannot be used interchangeably. The article will help you to learn which oil you need to use for different parts.

What is gear oil

What is gear oil

A lubricant for gears and differentials is gear oil. Gear oil contains many additives and a high quantity of chemical compounds that preserve the transmission or differential gears and bearings.

Gear oil is a thick substance that is used to lubricate and move the metal elements of the transmission apart from each other. Inside the gearbox, there were several metal-on-metal frictions. It generates a lot much heat and wears.

Furthermore, gear oil protects these moving parts by minimizing friction inside the gearbox, resulting in reduced heat and corrosion.

What is engine oil

What is engine oil

The lubricant that arrives in the engine area is engine oil. Engine oils aren’t designed to lubricate gear’s parts rather it is dedicatedly engineered to lubricate the engine’s parts. The engine is composed of moving parts, pistons, rods, crankshafts, valves, and bearings.

Engine oil is a blend of purified petroleum and a combination of beneficial additives. Diesel engines require engine oils that are developed particularly for them. Engine oil’s main purpose is to keep your engine parts cool and lubricate them properly for smooth and efficient operation.

See the Difference Between Engine oil vs. Gear oil

Engine Oil vs.

There are many differences between engine oil and gear oil in terms of their use and functions and also in appearance which are described below:


Engine oil is often lighter in color and appears golden. They darken with time as a result of the extreme heat and pollutants. There are several engine oils available, each with somewhat distinct looks and specs.

Gear oils are a little thicker than engine oils, and they’re normally tinted a light color to help you spot any leaks quickly. Depending on the sort of fluid you are using, they might be red, green, or even colorless.


Engine oil’s primary duty is to lubricate and cool your engine’s components, contemporary engine oils also handle a variety of other tasks, including:

  • Improves sealing,
  • Provides anti-corrosion and rust protection.
  • Contaminants are removed.
  • Keeps the temperature steady.

Gear oils have the following functions:

  • Improves the seal
  • Cools and transfers heat effectively.
  • Keeps hydraulic operations running.
  • Gears, resistance plates, bands, and the complete hydraulic system are lubricated.
  • Contaminants are eliminated.
  • Protects gears against corrosion and rust.
  • Allows for seamless transitions.


Engine oils are made by combining many substances to improve their qualities. The following are some of the most common additives used in contemporary engine oils:

  • Inhibitors of corrosion
  • Liquid antifreeze
  • Inhibitors of foam
  • Wear inhibitors
  • Dispersants/antioxidants
  • Improves the viscosity index

There are more additives in gear oils.  The following are some of the additives used in gear oil and transmission fluid:

  • Compressors for gaskets
  • Improves cold flow
  • Thickeners with a high melting point
  • Modifiers of Friction
  • additives to prevent wear
  • Depressant point pour
  • Surfactants, detergents, and dispersants are all types of chemicals that are used in the manufacturing of products.
  • Modifiers and enhancers of viscosity


Due to extreme heat and pollution, engine oils get contaminated and darken with time. Your engine will need to be serviced regularly to maintain it in top shape. Around 3000-5000 kilometers, you need to change your engine oil.

Gear oils operate in a closed loop, are seldom exposed to greater temperatures than engine oil, and get into touch with fewer impurities. As a result, they do not require frequent replacement. Once every 50,000-100,000 kilometers is sufficient.


The basic oil stock occupies up to 95% of the available space and has the ability to lubricate engine components. To improve the performance and qualities of your engine oils, several additives with various properties are mixed into the base stock. By nature, they are alkaline.

Engine oil and transmission fluid are similar in appearance. The primary functions of base oil are lubricating and hydraulic pressure. Later-added additives and colors give gear oil its distinguishing qualities and look. Acidic gear oils are used.

Where gear oil comes to play

  • Transmission
  • Differentials
  • Manual gearboxes
  • Transaxles
  • Transfer cases

Gear oil keeps these machines running smoothly. Furthermore, the lubricant protects various internal gear system units from stress and heat damage. Gearbox noise can also be reduced by using high-quality gear oil.

Where engine oil comes to play

  • Fuel pumps
  • Bearings
  • Other moving parts of the engine


Can engine oil be used as gear oil?

No. Cars, trucks, aircraft, and other vehicles have diverse engines. Most of the time, your motor oil cannot be used for a certain engine. Just use gear oils that are made exclusively for your motorcycle.

What happens if I use gear oil in the engine?

Gear oils include sulfur/phosphorus compounds that may severely harm the internal components of your engine, rendering it worthless.

What does engine oil number mean?

The figures often pertain to the thickness of the oil solution in question. They represent the difference in oil viscosity between the two temperatures.


Engine Oil vs. Gear Oil two

The differences between gear oil and engine oil are important to know before using them. Because the wrong use of oil can cause serious and expensive damage to your car parts. The article will help you to learn the differences, use, and importance of both oil.

Related Post:

  1. How does an oil filter work? Detailed Guide for Beginners
  2. How Long Does it Take for Oil to Turn Black?
  3. What Motor Oil is High in Zinc