Can I Use Motor Oil For Transmission Fluid?

Each fluid or oil plays a vital role in the car’s overall running, whether it is motor oil, transmission oil, gear oil, and so on. Each oil is important for its own purpose and help ensure smooth running. You may not be able to use the same oil for different purposes. Before you try using an oil, make sure you have checked the results.

This article will discuss motor oil. transmission fluid. You may be wondering if motor oil can be used as transmission fluid. Please read this article. Let’s get started!

Also read: Can You Use Vegetable Oil For Engine Oil?

Can I Use Motor Oil For Transmission Fluid?

You can’t, and you shouldn’t use motor oil in place of transmission fluid. Any oil other than the one it was designed for can cause damage to your car and reduce its performance. However, certain oils and fluids can be interchangeably used. There are many other things you can use. instead of power steering fluid Motor oil, however, is not one.

It depends on many factors whether motor oil is suitable for use as transmission fluid. Let’s take a look at their composition before we move on.

What is Motor oil made of?

Motor oil is a petroleum-based, oil that contains more than 75% of the base oil. other additives Important for lubrication. There are three types of motor oil: synthetic oil (non-synthetic), and mineral oil. All of them contain some petroleum, either crude or refined. 

Also read: Can You Mix Gear Oil With Engine Oil?

Motor oil is used primarily for the lubrication and maintenance of engine parts. There are many additives in motor oil that make it a good lubricant. Other than lubricants there are other additives such as detergents, antiwear and tear, viscosity related additives, and antifreeze additives that can help improve the quality of motor oils.

What is Transmission Fluid Made From?

Transmission fluid can be divided into two types: Automatic Transmission Fluid(ATF), and Manual Transmission Fluid(MTF), but they have almost identical compositions. Transmission fluids are made up of crude oil and easter, which is the base oil. They also contain additives, just like motor oil.

Manual Transmission fluids weigh more than automatic transmission fluids. Both play a significant role in the smooth shifting and control of gears. Transmission fluid is also used to cool and lubricate parts of the gearbox, or the entire gear system. It prevents wear. 

It is evident that they both serve one purpose: the lubrication and maintenance of the parts. However, motor oil cannot be used as transmission fluid.

Let’s look at the differences based upon various factors.

Difference between Motor Oil and Transmission Fluid

FactorsMotor oilTransmission Fluid
CompositionMade up of more than 75% base oil It is petroleum- and hydrocarbons-based. It can also contain several additives.Transmission fluid is made up of crude oil and base oil. It also contains some additives.
TypesMajorly of three types: Mineral Motor OilSynthetic Motor OlSemi-Synthetic Motor OilThere are two types: manual transmission fluid (ATF) and automatic transmission fluid (MTF).
ViscosityMotor oil’s viscosity at operating or running temperatures is approximately 10 centistokes. However, this depends on the type.Transmission fluid has an average viscosity of about 7.5 centispokes at operating temperatures. This depends on the type and use of the transmission fluid.
UsesMotor oil is used for engines. It is used to lubricate parts of the engine, protect them from excessive heat and cool the parts.Transmission fluid is used to lubricate the gearbox or transmission system. It is used to lubricate parts, provide protection against breakdown or failure, smooth or frictionless shifts of gears, and, in the case ATF, also provides pressure for the automatic gear shift.

We have now a good understanding of the components of transmission fluid and differences between them. Now it is time to find out why motor oil should not be used for transmission fluid. 

Also read: What Can I Use Instead Of Power Steering Fluid

Why should I not use motor oil for transmission fluid?

Motor oil is not recommended for use as a transmission fluid. Although they share one purpose, the lubrication and maintenance of parts, they are both different. Because of some additives, using motor oil as transmission fluid may not be safe.

On operating temperature, motor oil is slightly viscose than fluid. It is also slightly thicker than transmission fluid. It can cause poor performance in shifting gears and could lead to strange sounds from the bearings. 

The use of motor oil as transmission fluids could also cause the gears to slip. ATF is a particular case where the motor oil doesn’t have the proper pressure to enable the automatic shifting of the gears. 

Worst case scenario, the car might not work properly when in gear. This can lead to dangerous situations. You should therefore avoid using motor oil as transmission fluid.


Motor oil is not recommended for transmission fluid as they are both designed for specific purposes. If used as transmission fluid, motor oil can cause damage to the transmission system. It can also lead to poor performance and difficulties in shifting gears in both the manual and automatic modes. Motor oil cannot be used as transmission fluid.

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