Can I Use Motor Oil For Transmission Fluid? (Explained!)

If we talk about motor oil and transmission fluids, they are essential fluids required by a vehicle to perform optimum performance and function at its total capacity. But can motor oil be used as a transmission fluid? Let us find out the answer.

So can you use motor oil for your transmission fluid? The answer is no. The job of transmission fluid is for your gear system and your steering, while on the other hand, the motor oil is made to function in a vehicle’s engine.

Now, both these fluids have their similarities. However, you must not use motor oil as a replacement for your transmission fluid. Many people are confused about the differences or similarities between motor oil and transmission fluids. 

Some people would also interchange both these fluids, and as a result, they have experienced engine issues and problems in their vehicle. So with this article, you will learn everything there is to know about motor oil and transmission fluids. Let us start.

Can I Use Motor Oil For Transmission Fluid

Can Motor Oil Ruin A Transmission?

Yes, motor oil can ruin a transmission and the transmission system. When we talk about motor oil, its primary function is to improve the sealing and prevent rust on the different components of the engine. It also keeps the engine parts of the vehicle free of any sludge. 

It even cools down the system of the vehicle’s engine. And lastly, it reduces the friction in your engine system. On the other hand, the function of transmission fluid is to help in improving the operation of your auto and manual transmission. 

When it comes to the differences between these fluids, the motor oil is concentrated on the engine area that handles the combustion. The transmission is different because it provides lubrication to the transmission system of the vehicle. This will provide swift engagement to your clutches and your gears.

Is It Bad To Put Motor Oil In Your Transmission?

If you replace the transmission fluid with motor oil, it can do some dire results for your vehicle. However, some people would also say that adding motor oil to your transmission might not have a dangerous result. So if you will only add motor oil and not replace the whole thing, it might also not do any severe damage. 

You have to go to a transmission shop to remove the motor oil in your transmission. You can do it by yourself, but you will need knowledge in doing this. It is pretty challenging to remove the wrong oil from your torque converter. 

If you already noticed that there is motor oil in your transmission, do not drive your car so that you will avoid any damages. Instead, dump the oil and refill your oil. 

With that, there might be no damages to your vehicle. However, if you have driven your car, get the trans flushed.

What Happens If I Put Motor Oil In My Transmission Fluid?

If you have put motor oil as your transmission fluid, there are a few possible problems that you can encounter. The severity of the damage will depend on how much motor oil you have poured in your transmission and how long you have been driving your car with the wrong fluid. Here are the things that can happen if you have put a lot of motor oil in your transmission and have been driving your car for a very long time with the wrong fluid.

1. You Might Hear Noises When Driving The Vehicle

Putting the wrong type of fluid in your transmission system will create many kinds of noise when driving. The motor oil can cause noises that are coming from your transmission system.

2. When In Gear, Car Might Not Function

Putting motor oil in your transmission system might cause a delay in the response of your vehicle while in gear. In addition, the transmission might not also work if you reverse or you are driving your car. This is because motor oil has properties that cannot do the function of transmission fluid.

3. You Might Experience Gears Slipping

There is also gears slipping, and if this will occur, you are experiencing a significant safety issue. You might have to have this repaired and fixed immediately. On the other hand, you do not want to have to deal with gear slipping.

4. You Might Smell Something Burning

If you smell something burning in your vehicle, you might have an overheated fluid in your transmission. Though a burning smell can mean so many things, if you have put engine motor oil in your transmission, this can cause. This can happen because the transmission fluid contains a high lubricating property. 

This lubricating property is preventing any form of damage in between the meeting parts. So if the transmission system is not properly lubricated because of putting the wrong fluid, it can significantly damage your transmission system.

5. There Can Be Grinding Sensation In Your Gear

Inputting the correct transmission fluid, its function is to help the automatic transmission system to operate smoothly. So now, if you use the wrong fluid-like motor oil, it can cause nasty things on your vehicle’s transmission system. 

As a result, you can feel some shaking movements or even grinding movements if you change gears. This can be because the seals or the o-rings are damaged.

What Can Be Used In Place Of Transmission Fluid?

You can use a power steering fluid as a replacement for your transmission fluid. The rule of thumb is to always refer to your owner’s manual. There, you will find everything you need for your vehicle. 

In addition, you can find the recommendations of the car manufacturer. For example, using a power steering fluid can be okay. This is because transmission fluid and power steering fluid mixed well together. 

This is better to use rather than engine oil. However, it can do significant damages to your vehicle. Transmission is a hydraulic fluid, and power steering fluid is also a hydraulic fluid.

Does Transmission Fluid MIX With Engine Oil?

Well, yes, they do mix. Many people are putting a little bit of engine oil on their transmission fluid for they believe it to be beneficial to their engine. 

They believe that the engine oil can clean the engine. However, if you put a lot of motor oil, it is best to change it as soon as possible to avoid any problem.

How Can You Tell The Difference Between Transmission Fluid And Oil?

There are quite a few differences between transmission fluid and motor oil. In terms of function, the motor oil is designed for the system of the engine. It will eliminate the friction that is caused by the components in the engine system. 

It will also keep the system from having any rust and will be free of any sludge. On the other hand, the transmission fluid is focused on the system of the vehicle. Therefore, the transmission fluid will ensure a smooth operation of the clutches and the gears in the transmission system. 

In terms of the lifespan, the motor oil will decrease over time and on the mileage. You will also have to change your motor oil every three thousand miles or six thousand miles.

On the other hand, the transmission fluid will not decrease over time and on the mileage. So you will not also have to change your transmission now and then. In terms of color, motor oil will usually be gold or bright yellow if it is still fresh and new. 

After some time, though, it will turn black. On the other hand, the transmission fluid has the color red.

Why Does My Transmission Fluid Look Like Oil?

The physical look and the color of your transmission fluid are usually red or brown. It is also thick and also slick like oil. Next, you can check if your transmission fluid is healthy. 

If your transmission fluid is healthy, it is primarily pink or red. However, if the transmission fluid turns brown or even black, your transmission fluid is dirty.

A Small Amount Of Motor Oil In Transmission: Is It Okay?

If you have a small amount of motor oil in your transmission, it is possible that your vehicle will be okay and will have no significant damage to your car. However, you must flush it immediately. 

It would help if you did not take any chances. For example, if you have put in small motor oil, it will not create damages if you are not driving your car and immediately taking out the motor oil.  

Can Engine Oil Get Into The Transmission?

This is very unlikely. It is just about ninety-nine percent impossible for engine oil to travel and get into the vehicle’s transmission.

Engine Oil Mixed With Transmission Fluid: What To Do?

Let us get this straight. If you have accidentally put some engine oil as your transmission fluid and have not driven your car, you will experience nothing serious. So it would be best if you acted fast. 

First, do not drive the car and remove the transmission oil pan. Next, you have to drain everything and replace the filter. After that, you can now install the pan back, and then you have to refill it with a new transmission fluid. 

After that, you can start and drive your car for a day and then do the same thing again. This is to ensure that you have left no engine oil in your transmission.


In summary, this guide will help you in almost everything there is to know about putting motor oil and using it to replace transmission fluid. Although the motor oil and transmission oil might have a few similarities, they also have some differences. 

They have different functions and purposes. Do not attempt to replace your transmission fluid with motor oil. There is a reason why it is essential to use the correct fluid in operating your vehicle.

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more