Is Engine Oil The Same As The Transmission Oil ?


In a car, there are several oils, the most frequently changed are engine oil and transmission oil.

Then is engine oil the same as transmission oil? if not, what's the difference?

In fact, engine oil is very different from transmission oil. Based on their function, transmission oil and engine oil are used in different conditions. Therefore the oil composition is also different.

To be clear, I will give several different types of oil in cars.

1. Engine oil

Engine oil is used to lubricate the inside of the engine, oil used in gasoline engines is also different with oil used in diesel engines.

Gasoline engine oil is designed to be smoother, equipped with friction modifiers to produce a very low coefficient of friction, and is equipped with detergent and anti-wear additives.

These additives have the ability to absorb moisture and then evaporate when it is hot. Oil on a gasoline engine, tends to be slippery. So it is not suitable for any type of transmission.

In diesel engines, anti-wear additives and detergents have higher levels. It aims to make the diesel engine able to last longer in high compression pressure conditions.

Diesel engine oil also has the ability to absorb moisture and release it when it's hot.

Due to the harsher nature of diesel oil, many believe that diesel oil is can be used for transmissions (Isuzu, and some Chevrolets).

2. Motorcycle engine oil

Unlike a car, a motorcycle only has one type of oil even though a motorcycle also has a transmission.

This is because motorcycle engine oil (4 stroke) does not contain a slippery friction modifier, so that the oil on the motorbike can be used to lubricate the engine, wet clutch, and the transmission.

Another on the scooter matic, where this vehicle uses a CVT and centrifugal clutch. So the oil is only charged to lubricate the engine, so that the physical properties of the oil are almost the same as car engine oil.

3. ATF (automatic transmission fluid)

Automatic transmission oil is oil with multiple capabilities. This oil can lubricate the mechanical parts of the transmission, withstand high pressure, can withstand high temperatures, and it is function as a coolant fluid.

ATF is not just oil, but a hydraulic fluid in an automatic transmission that operates the transmission directly.

So of course this oil cannot be used in the engine.

4. Manual transmission oil

Manual transmission oil is a pure lubricant whose main function is to lubricate the gear parts in the gear box.

As a lubricant, this oil has the ability to dampen vibrations, prevent slippage, maintain gear temperature, and can last for long-term use.

The main characteristic that distinguishes manual transmission oil from engine oil is its viscosity. Manual transmission oil is thicker than engine oil. These are typically available in 75W-80, 75W-85, 75W-90, and 80W-90 viscosities.

So in conclusion, the engine and transmission have significant differences. The engine is dominated by components that rub against a narrow gap, so that the oil in the engine must be able to enter the narrow gap and be able to smooth out any friction of the component.

Meanwhile, the transmission is dominated by mesh gears. So that the suitable oil is oil with anti-slip capability, so that the transmission can operate smoothly.