How you can use transmission fluid for power steering

Wondering if you can use transmission fluid for power steering?  What fluid you can use for power steering if not power steering fluid?  Read on.

Let’s address the question of whether you can use transmission fluid in place of power steering fluid if you are servicing your vehicle.  As a car owner, you want to make sure that you take care of all the necessary maintenance?  You know it makes sense to take care of your vehicle so that it doesn’t break down on you and it keeps running without any issues.

If you are considering taking on some of the tasks yourself rather than entrusting your car to a garage and paying their huge bills then questions like ‘Can I use transmission fluid in my power steering?’ become more important.

There are many fluids involved in the running of a car – transmission, power steering and brake all need addressing and either topping up or flushing out to keep everything running smoothly.

Now whilst it is always great to check out your car owner’s manual – and to make sure that you have everything necessary on hand, on occasions you may want to make a substitution as long as you know this can be done without any ill-effects.

If you are substituting transmission fluid in place of power steering fluid then you need to know that it depends entirely on the make and model of your vehicle.  Whilst it is best to err on the side of caution,  you will have a more successful result from a Ford or GM model than you will if you are running a BMW, Audi, Mercedes or Honda.

Historically they were interchangeable, and so you will find many old school recommendations to use either – the more modern approach, with the advances in car technology as well, are that the substitution should only be made if you have an emergency situation.  Not since the late 1970s has it been completely fine to change the two in any vehicle.

The wrong fluid in large amounts can cause destruction and deterioration in the system parts of your car.  If you use AFT fluid in your power steering long term use will affect both the pump and the gearbox seals – not something that you want to deteriorate on you, and an expensive fix.

Back in the day, there were no sophisticated or lightweight materials in the vehicles construction – in fact, when you go back to the mechanics now they look crude in their development by comparison with modern vehicles.

The more modern construction uses delicate parts and precision engineering that will work better, and for longer, if you follow the exact guidelines and use liquids designed for the purpose.

How do Power Steering Fluid and Automatic Transmission Fluid Differ?

Making any decision is better when you understand the properties and benefits of a product.  So, whilst ATS and PSF are both hydraulic fluids, they are not the same as each other.


Automatic Transmission Fluid contains both detergents and also friction modifiers.  The detergents filter grease and dirt away from the powered steering system and could cause damage to the hydraulic valves on the steering rack, the friction modifiers affect the valve and pump heat build-up.


Power Steering Fluid is used to lubricate and reduce friction between the various components of the power steering.  Automatic Transmission Fluid is used more for friction and cleaning.  Power Steering Fluid is also used to reduce any excessive build-up of temperature, lubricating the steering pump and gear unit whilst providing hydraulic pressure within the system parts.


Power Steering Fluid is pinkish, amber or clear and smells a little like a burnt marshmallow.  It ages into red or brown.

Automatic Transmission Fluid has a unique sweet smell – not like burnt marshmallow though – and is red.  It also darkens through time to an orange.

Can you mix transmission fluid with power steering fluid?

It is never a good idea to mix any car fluids.  The same issues would be caused by a mix, as by utilizing the incorrect fluid.

Can you use transmission fluid for power steering fluid?  You can in an emergency, you can if you have an older vehicle, it is likely to cause less damage if you are driving a Ford or GM vehicle.   If you are undertaking routine maintenance though or planning to do some work on your car then check your owner’s manual and buy the correct product.

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