Can You Mix Synthetic ATF with Regular ATF?

Yes, you can. Synthetic ATF and traditional fluids are completely interchangeable.

Automatic Transmission Fluid (ATF) Dexron-IlI is developed to meet the most stringent performance requirements of many heavy-duty trucks, both on and off the road.

What is Synthetic ATF?

Synthetic ATFs are created from refined oils that have been treated with various chemical additives. The first was made from polyalphaolefin (PAO), which is classified as a Group IV oil by the American Petroleum Institute (API). Diesters, alkylated napthlenes,polyolesters, and alkylated benzenes are used to make non-PAO synthetics, which are classed as Group V oils by API. Synthetic transmission fluids have been found to keep their viscosity for longer periods of time than conventional transmission fluids, reducing the frequency with which they must be replaced.

Can various transmission fluids be mixed, for example?

Because they employ different additives in the fluids, some transmission fluids are incompatible with different transmission types. While it's not unusual for individuals to mix up which fluids should go in their car, using the incorrect transmission fluid might result in your vehicle's premature end.

Is synthetic automatic transmission fluid a better option?

Synthetic ATFs' lower operating temperatures can make a huge difference in component longevity. The best automatic transmission fluids typically claim to increase vehicle fuel mileage, but replacing the fluid almost always achieves that goal.

What are the advantages?

Synthetic ATF has some advantages over mineral-based transmission fluids. Synthetic transmission fluid is less likely to break down in high-heat environments, allowing the transmission to last longer.

According to Mobil and Valvoline, both of which offer synthetic and mineral-based transmission fluid for a range of automobiles, mixing regular ATF and synthetic transmission fluid is allowed. Even premade mixtures of synthetic and mineral-based transmission fluid are available from manufacturers.

When adding fluid to a low transmission, car owners may want to blend synthetic ATF with regular ATF. Because synthetic transmission fluid is more expensive than mineral-based transmission fluid, mixing the two when the fluid is changed is a way to save money while still getting some of the benefits of synthetic transmission fluid.

Do not forget

You will have no problem if you own an older vehicle that runs on regular mineral-based transmission fluid and you top it up with Synthetic ATF. It will function normally in this aspect. Because the synthetic equivalent often has a lower viscosity, the shifting may become a little smoother.

If you have a gearbox that needs complete synthetic fluid and you top it up or switch to mineral-based fluid, you're taking a big risk.

There's a reason why the manufacturer specified synthetic. It could simply be to increase the time between changes, in which case nothing bad should happen if you replace your mineral oil more frequently.

However, it's possible that the synthetic is required by the transmission's design to function properly or to maintain enough lubrication on severely strained parts. You're in considerable danger of transmission failure in this situation.

There’s no way of knowing – this is the problem. So, if you're looking to save money by switching to a cheaper oil, don't do it. You will have to pay a more hefty price in the long run.


It is critical to utilize the right transmission fluid specified for your vehicle, whether it is synthetic or mineral-based. The owner's manual for the vehicle has the manufacturer's suggestion for the right type of transmission fluid to use.

Automatic Transmission Fluid (ATF) Dexron-IlI satisfies extreme pressure gear to provide optimum protection for vital components, such as the rear axle and differential, in on and off-road vehicles running in extreme heat or cold.

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