Can You Use Transmission Fluid for Power Steering Pump?

Flushing the fluid of the transmission, radiator, brake, and engine is part of a regular maintenance schedule of a car. Does the power steering also need flushing? If it does, can you use transmission fluid for power steering pump? Is there any possibility of ruining the power steering components by doing so or do both fluids have the same properties? If you are thinking of using the transmission fluid in power steering, this article will help you get the answers.

Is a Power Steering Flush Necessary?

Any automobile with a hydraulic power-steering system needs power steering fluid. It works with the power steering pump to make turning the steering wheel smoother.

Over time, the fluid collects metal particles and sludge. The thick grit looks like sand that gets into the rack and pinion seals and ruins them ultimately.

The owner’s manual does not list the flushing of the power steering fluid as routine maintenance. But, you have to do it to keep the car in good condition. When flushing becomes compulsory rather than an optional task, many people come up with the question – can I use transmission fluid for power steering fluid? Let’s find out the differences between the fluid types before answering the question.

power steering fluid vs atf
Flushing the old fluid is necessary. (Photo: gobdp)

Power Steering Fluid vs ATF

Many people want to know if they can use the transmission fluid in the power steering pump. Is power steering fluid the same as transmission fluid? A comparison between them will help you to understand whether replacing one fluid with the other is safe.

The automatic transmission fluid (AF) is a red color liquid that releases a distinct sweet smell while the power steering (PS) fluid is clear, amber, or pinkish and smells like burnt marshmallows.

Both of them are hydraulic fluids. But, the biggest difference is ATF contains detergents and friction modifiers. The detergents filter grease and dirt that may go into the power steering system and damage the pump and steering rack’s hydraulic valves. The friction modifiers, on the other hand, keep the excessive heat buildup of the valves and pump in check.

The PS fluid also reduces the friction between various components in the system and excessive temperature buildup. Its other jobs are providing hydraulic pressure to the system’s components and lubricating the steering pump and gear unit. But, can you use transmission fluid for power steering pump? Let’s find out.

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Can You Use Transmission Fluid for Power Steering Pump?

It depends on the make and model of the vehicle. Some people don’t see any problem while others are completely against it unless it’s an absolute emergency.

The argument against the practice seems stronger because using the wrong oil in a high volume can deteriorate and destroy the parts of a system. The ATS and PS fluid are both hydraulic types but they are not the same thing.

The transmission fluid is for cleaning and friction. Being gluey and heat-resistant in nature, it enhances friction between components in the clutch pack for better grips. On the contrary, the PS fluid is mainly for lubrication and reducing friction between various parts of the power steering system. The ATF will work for a while it will affect the seals of the pump and gearbox in the long run. Using the PS fluid approved for the model of your vehicle is the right way to avoid any trouble.

Is It Possible to Replace the PS Fluid with Transmission Fluid In Any Vehicle?

So, can you use transmission fluid for power steering pump? The answer is ‘no’! Then, why do so many people talk in favor of it?

Well, you can use ATF in the power steering pump in vehicles manufactured in the late ‘70s or earlier. Those older cars don’t have the sophisticated and lightweight materials used in the cars produced in the ‘90s and later. The power steering system of old vehicles is made of crude materials that can take ATF because it is also a hydraulic fluid.

Modern cars have subtle engineering and delicate components. Each system needs the oil and fluid that is specially designed for them. So, using a different fluid that does not meet the requirements of a specific system is harmful to it.

can i use transmission fluid for power steering fluid
You can replace the fluid in older cars. (Photo: Wikimedia)

Many Ford and GM models are fine with the fluid swap while you will simply ruin a BMW, Audi, Honda, or Mercedes-Benz by doing so. The best way to determine the answer to the question – can you use transmission fluid for power steering pump – is to check your car’s owner’s manual. It will clearly mention whether the car needs the standard power steering fluid or can run with ATF too. Some models may require specific types of hydraulic fluid. For instance, a Lexus LX470 will be fine with ATF but a BMW requires a special synthetic fluid called Pentosin CHF 11S. If your car was manufactured in the ‘90s or afterward, do check the owner’s manual before making a rash decision.

Should We Mix The Transmission Fluid With PS Fluid?

The ATF is basically used to reduce friction and for cleaning while the PS fluid is mainly used for lubricating the power steering parts. But can we mix two types of fluids with each other? As we know the PS fluid and transmission fluid are both hydraulic fluids, so mixing them isn’t supposed to be an issue. However, because they both have different material compositions in them, it may lead to a problem if mixed together and some definite requirements are not met.

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One thing to note is that the power steering fluid has oil present in it while the transmission fluid doesn’t have any oil element in its formula. So, it’s very much possible for there to be leakages if these fluids are used in one system with rubber parts because oil can cause the rubber to expand. Based on this, the power fluid may cause a problem.