8 Best Transmission Fluids in 2024: Reviews & Top Picks

Unless you’ve changed all your vehicle’s fluids before, you probably haven’t given much thought to the type of transmission fluid in there. But it’s an important thing to think about if you’re not hiring someone to change the oil.

Aside from ensuring that you’re using the correct type, there are several brands to choose from. These reviews will go over eight of the best options available and tell you a bit about each of them. After the reviews, a short buying guide details the importance of choosing the correct transmission fluid for your vehicle.

A Quick Comparison of Our Winners (2024)

The 8 Best Transmission Fluids

1. Royal Purple High-Performance ATF – Best Overall

If you’ve visited the auto parts store to purchase any oils for your vehicle, you’ve probably heard the name Royal Purple. It is one of the leading brands of high-quality oils and fluids for vehicles.

In addition to its lubrication, this high-performance automatic transmission fluid (ATF) helps reduce heat in the transmission because of its high film strength. The primary reason this is the best overall transmission fluid is because of its ability to mix with any other transmission fluid and also because it’s compatible with all brands of automatic transmission.

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2. Valvoline ATF – Best Value

Valvoline is well-known as one of the major producers of automotive oils. This ATF is mostly universal other than not meeting the specifications of some imports. If it’s compatible with your vehicle and you’re looking for the best transmission fluid for the money, this is an excellent pick.

With a proprietary blend of base oils, this Valvoline ATF offers excellent flow at low temperatures but maintains excellent film protection at high temperatures. It also has additives that help protect internal transmission components from rust and corrosion.

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3. Liqui Moly Top Tec ATF – Premium Choice

Another of the top fluid producers in the world is Liqui Moly. They have a massive selection of oils and fluids for any type of vehicle maintenance. This ATF is a little pricier than most but worth the money if you have a newer vehicle in which you want to run premium oil.

Because of its viscosity, this ATF offers superior, smooth shifting under all operating conditions. The high-performance additives it contains help reduce its aging and oxidation and prevent foam formation in your transmission fluid.

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4. ACDelco ATF

If you own a GM vehicle, ACDelco is the OEM brand for nearly every component. The best part about using an ACDelco ATF in your car is you know that it meets every single specification . It may not meet the requirements of any other brands. However, with the ACDelco ATF formulation, your vehicle receives a long-lasting ATF that offers superior shifting performance, even under extreme operating conditions.

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5. Torco MTF

Manual transmissions are not nearly as common nowadays. But if your car is a newer manual that requires a GL-5 manual transmission fluid (MTF), this one by Torco is an excellent option. It’s formulated for racing and performance.

The additives it contains help prevent corrosion, foam, and oxidation. However, compared to other MTFs, it does have shorter intervals between fluid changes. This makes it a pretty expensive option. But if you don’t mind the cost, it’s one of the best MTFs you can get.

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6. Mobil 1 ATF

Mobil 1 has long been considered a superior brand in the oil industry. And if this ATF meets your vehicle’s specifications, it’s a great option. However, it does have limited compatibility and cannot mix with other oils. So, depending on how big your transmission is, it can get quite pricey.

Being a fully synthetic oil, it contains additives that offer outstanding wear protection for your transmission. Plus, it has additives to help prevent thermal breakdown, so it performs well even under extreme conditions like pulling a trailer or driving over hills.

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7. Redline MTF

Red Line is another brand name often associated with high-performance and racing applications. This MTF is suitable for older transmissions that require GL-1, 3, or 4. Because of the formula’s balance between slippery and friction control, it offers superior gear protection while shifting. Because of the temperature and wear protection it provides, Red Line is an ideal MTF if you plan on going off-road with your vehicle.

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8. Castrol High-Mileage ATF

As vehicles age, seals start to leak, and corrosion builds up. With this high-mileage formula from Castrol, you may be able to breathe some new life into your transmission if it’s not too far gone. It contains special conditioners in the fluid that lubricate and refresh seals to prevent leaks. If a leak isn’t too bad, the conditioning may also be able to stop it.

In addition, it contains other additives to deal with problems specific to older transmissions, like varnish and sludge buildup. You can use it on any vehicle that it meets the specifications for, but there are better options if you have a newer vehicle.

Buyer’s Guide: How to Select the Best Transmission Fluids

At the end of the day, many of these brands offer very similar formulations, and in some instances, it simply comes down to brand preference. However, each transmission has specific requirements, so there are some things to keep in mind. This buyer’s guide will give you a crash course on what the transmission fluid does and what specific things to look for when deciding on a brand.

What does Transmission Fluid Do?

Transmission fluid is responsible for several things. Its primary job is to lubricate the components within the transmission, but it also helps prevent corrosion and rust from building up, and it also helps keep oxidation at bay. Transmissions get very hot, especially when pulling a trailer or driving up hills. So, the fluid is also responsible for keeping the transmission temperature under control.

Importance of Changing Transmission Fluid

Over time, transmission fluid gets dirty and begins to break down. Most manufacturers include additives in their transmission fluid to help slow this down, but it eventually happens. Changing the fluid according to your vehicle manufacturer’s recommendations is important to maintain sound transmission health and prevent expensive fixes down the road.

Buying the Right Fluid

Aside from buying a high-quality transmission fluid, there are several other factors to consider when deciding which brand to use.

Synthetic vs. Non-Synthetic

There are not many non-synthetic oils and fluids out there anymore. However, they do exist. Typically, a non-synthetic is inferior to a synthetic fluid. But in some cases—like with older vehicles—a cheaper non-synthetic is suitable. Also, if an old vehicle has always had a non-synthetic, a synthetic fluid can sometimes cause it to begin leaking because of the difference in viscosity.

Transmission Fluid Type

Other than automatic and manual, there are certain specifications that each transmission requires. For example, Dexron is a GM spec, and Mercon and F-type are Ford specs. Consult your owner’s manual and ensure the fluid you choose meets the correct specification.

Age of the Vehicle

One factor that age affects is fluid type. For example, there are six generations of Mercon fluids, and the latest generation works in most vehicles. In addition to the fluid type, an older vehicle will benefit from different additives than a new vehicle. A high-mileage formula will work in a new car, but it won’t reap many benefits.

Conclusion

After reading these reviews, we hope you have a good idea of which transmission fluid is best for you. The Royal Purple ATF remains the best overall pick for its high-performance formula, but if you’re looking for a budget-friendly option, the Valvoline ATF is a great pick. However, if you’re one of the few people still driving a manual transmission vehicle, Torco’s MTF is one of the best fluids you can treat the transmission with.

You may also be interested in: How Often Should I Change the Differential Fluid in My Car?

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Featured Image Credit: Oteera, Shutterstock