10 Best Transmission Additives in 2024: Reviews & Top Picks

Transmission additives are designed to address various transmission problems. You simply add them to your transmission fluid, and you may notice a reduction in erratic shifting, leaks, and similar problems.

However, not all transmission additives are the same. Some do not do much at all, and others can even make problems worse. Therefore, it is vital that you choose only high-quality transmission additives. Below, we’ve reviewed some of the best transmission fluid additives on the market. Many of these have great reviews and may help with some of your problems.

A Quick Comparison of Our Winners (2024)

The 10 Best Transmission Additives

1. Prolong Super Lubricants PSL15000 Transmission Treatment – Best Overall

Out of all the brands on the market, the Prolong Super Lubricants PSL15000 Transmission Treatment is easily the best overall transmission additive. While many transmission additives do not do anything, Prolong delivers. It is easy to see why it is one of the most popular options.

It works by producing molecules that interact with the surface of metals. The molecules coat the metal and work as a protective shield. Overall, it can help lower the heat and friction in the transmission system. In the end, many customers noticed improved gear changes. We recommend this lubricant for various cars, including everyday vehicles and those only driven on weekends. A single bottle goes a long way and can completely treat the whole system. It lasts a while since it chemically bonds to the metal.

However, it only works for CVT transmissions, so it is not recommended for all cars.

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2. Lucas LUC10009 Transmission Fix – Best Value

For those looking for a budget option, we highly recommend the Lucas LUC10009 Transmission Fix. Not only is it inexpensive, but it is also very good for slippage. It forms a film inside the transmission that helps protect bands and prevent the system from overheating. Therefore, it can prevent slippage and even cure slippage problems.

Lucas LUC10009 is a solvent-free formula that does not foam. On top of producing a film, it helps seal leaks and lowers the operating temperature of the fluid. If you have older transmission fluid, this formula can also help improve its quality. You may not need to change your transmission fluid as often, though that is not necessarily recommended.

This product is relatively new compared to the others we’ve mentioned, but it has worked well thus far. It can work on various transmission problems, including leaks and hard shifting. However, the Lucas additive is not a cure for all transmission problems. It may not work as well for serious problems, as it is not particularly heavy-duty. Still, it is easily the best transmission additive for the money.

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3. Lubegard 19610 Dr. Tanny Instant Shudder Fix – Premium Choice

Lubegard 19610 Dr. Tanny Instant Shudder Fix is a great option for preventing and fixing transmission shudders. It does a very good job of improving overall transmission performance, and customers are surprised by how well this transmission additive works. However, it is also more expensive than other options, so it is not for someone looking for a budget additive.

We liked that this concentrated formula is designed specifically to prevent transmission shudders. It also prevents wear, and you may want to use it even if your transmission is currently fine since it can prevent problems from occurring in the future. While Lubegard 19610 is designed for most cars, it is unsuitable for CVT applications.

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4. Hot Shot’s Secret

Hot Shot’s Secret is designed to clean your transmission, which can reduce and eliminate common transmission problems. It dissolves gum and varnish that may form in your transmission over time. It is suitable for gas and diesel automatic engines, and its primary function is to reduce the operating temperature of your transmission. However, Hot Shot’s Secret also works as a hydraulic fluid and lubricant. Therefore, it can do many jobs at once.

This formula will instantly attach itself to your car’s metal parts, which helps prevent deposits and grinding. Over time, this can reduce transmission wear and even reverse some wear that has already occurred.

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5. LUCAS Oil 10441 Automatic Transmission Fluid Condition

The LUCAS Oil 10441 Automatic Transmission Fluid Condition may not readily solve any of the problems you currently have. However, it may help prevent future problems. As the name suggests, this conditioner is only for automatic transmissions, which limits its use. It can prevent slippage, leaks, and general wear inside the transmission, but it is not designed to correct any of these problems once they start occurring.

Furthermore, LUCAS Oil 10441 can extend the life of your transmission fluid, allowing you to extend the time between changes. If you are a bit late on a change, you typically don’t have to worry about anything if you use this transmission additive.

You can use it on new and old transmissions, but it will not fix any existing problems—just prevent new ones.

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6. Lubegard 60902 Automatic Transmission Fluid Protectant

If you’re looking for a protective additive, you may want to consider Lubegard 60902 Automatic Transmission Fluid Protectant. It is designed to prevent overheating by reducing the overall operating temperature of the transmission. When used before problems erupt, it can prevent all sorts of common transmission problems.

Furthermore, it will eliminate foaming transmission fluid, prevent oxidation, and reduce wear. We recommend it for all cars with automatic transmissions, though newer cars are more likely to get something out of it. Because it improves the operating conditions of the transmission fluid, it can help the transmission fluid last longer. Therefore, Lubegard 60902 may help you save a bit of money over time.

However, it is a bit expensive, and the bottle is tiny. It is also only protective and doesn’t cure any problems you may already be having.

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7. Cerma Automatic Transmission Treatment

The Cerma Automatic Transmission Treatment comes in a much smaller bottle than most others. However, the bottle is enough for a complete treatment. You’ll have to purchase a new bottle every time you need to retreat (which can be expensive). Although it’s expensive, it’s one of the few that is designed to correct common problems.

For instance, it is designed to be used after your transmission starts acting up. You can use it to stop slippage and rough slipping. It works by lowering the operating temperature of the transmission fluid and sealing leaks. It can also reduce friction in the transmission, which helps eliminate many problems.

It only works in automatic transmissions, however. Plus, several reports show that it doesn’t cure serious problems, though many customers did see a small improvement.

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8. XADO Revitalizant EX120 Conditioner

Like most additives on this list, this conditioner is only designed for automatic transmissions. However, the same company does make an alternative option for manual transmissions. The size of the bottle is very small. In fact, it doesn’t come in a bottle at all. Instead, it comes in a small syringe.

Xado is advertised to help “rebuild” metal parts inside your transmission, which may help eliminate current problems. It also works as a protectant by preventing wear, reducing the chance of problems in the future. It prevents friction and reduces the operating temperature of your car’s transmission.

You can use it for most automatic transmissions, including CVT and Tiptronic. However, there are many reports of this conditioner not working very well. Furthermore, it has an average price, so we can’t group it with budget options, either. For this reason, it has a low value when you compare its effectiveness and price.

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9. BG ATC Plus

The BG ATC Plus is mostly designed to enhance your transmission fluid. It works on new and old transmission fluid to improve its functioning, which can help protect your transmission. It increases oxidation stability, prolonging the life of your transmission and saving you a bit of money.

Furthermore, it can prevent leaks by keeping seals soft and pliable. It may even be able to fix leaks caused by hardening seals, though that is debatable. In some cases, BG ATC Plus prevented the formation of sludge and other deposits.

However, it will not help eliminate fluid changes or work miracles on older cars. In fact, we only recommend it as a regular additive on new cars, along with regular transmission fluid changes.

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10. Bar’s Leaks 1416 Super Transmission Fix

According to the advertising, Bar’s Leaks 1416 Super Transmission Fix can correct certain transmission problems. For instance, it may reduce noise and renew worn seals. Many customers report that it seems to work on minor problems. However, just as many people were reporting that it didn’t work, so this seems to be a lower-quality additive (which makes sense considering the relatively low price).

It comes in a relatively large bottle—at least compared to many of the options on this list. However, you also need a lot of liquid to treat the average transmission, so don’t let the bigger size make you think you’re getting a deal. Sure, you’re getting more liquid, but you must use more during fluid changes.

Based on reports by those with much older cars, Bar’s Leaks 1416 seems to work best on newer cars. Most people with transmissions with over 100,000 miles did not notice any difference.

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

It can be challenging to tell different transmission additives apart from each other on the shelf. Often, they have very similar advertising that proclaims that each additive can prevent or cure a wide range of transmission problems.

However, there are some significant differences between these additives. They are not all interchangeable, despite the similar advertising. When choosing an option for your car, keep these factors in mind.

Compatibility

Most transmission additives are designed for automatic or manual transmissions. While picking up the incorrect additive won’t necessarily damage your car, it could. You don’t want to add an incompatible additive to your vehicle. At the very least, you’d need to do a complete fluid change after this mistake, which can be costly.

A manual transmission creates a lot of heat and friction. To withstand this, transmission fluid additives for manual transmissions often have a high viscosity and are designed to work under extreme heat. On the other hand, automatic transmissions are usually smaller and may have more moving parts. Usually, the additives designed for automatic transmissions have anti-foaming qualities and a low viscosity.

Fluid Type

There are two main types of transmission fluids: synthetic and natural. Synthetic is by far the most common. However, you should still check to see which type of fluid your car has before purchasing an additive. Many additives can only be used with certain fluid types, and things can get messy if you use the wrong additive.

Usually, the compatibility list will be located in the instructions on the back of the additive container.

Quality

Not all additives are made the same, as you might guess. Some are extremely high-quality and can treat several problems, while others may not work at all. Usually, the big-name brands have the best quality additives. However, these are usually also more expensive.

When in doubt, it is best to look at reviews like ours. Usually, using the additive is the only way to determine its effectiveness.

Purpose

Not all additives are designed to treat the same issues. Many products lower the operating temperature of the transmission fluid, but beyond that, they vary widely. You’ll need to consider the problems you’re having and find a transmission additive that can fix those problems.

Also, many are designed either to prevent problems or solve those that already exist. If you have a newer car, a preventative additive is likely what you need. However, these may not work well if your car is older and already experiencing problems.

Applications Per Package

Usually, when you see a large package, you assume that it contains a lot of applications. However, that is not necessarily true. Different additives require more liquid per application. This varies a lot. Some need whole liters per application, while others need a fraction of that.

When determining whether or not you’re getting a good deal, look at how much fluid you need per application. If you’re purchasing a bottle with two applications for an affordable price, you’re getting a pretty good deal. Compare the price of additives based on the number of applications in the bottle and not solely on the size of the package. In that case, a price-per-ounce isn’t a very effective measuring stick.

FAQs

Do Transmission Additives Actually Work?

Yes, to an extent. No additive can magically fix problems in your transmission. Instead, they simply optimize your transmission fluid. A car that uses a transmission additive will likely have less wear and fewer transmission problems. If your car already has transmission problems, there isn’t a lot that an additive can do.

These additives work far better when you use them throughout your car’s lifespan. Starting when your car is older may provide a few benefits, but much of the wear has already occurred.

Should I Use a Transmission Additive?

A transmission additive is a bit like insurance. No one can tell you whether or not you will use your insurance plan. However, if you need your insurance plan, you’ll thank yourself for getting it.

Transmission additives can prevent transmission problems. However, no one can tell you if your car will end up with a transmission problem later or if it’ll be sold before that ever happens. However, if you don’t use transmission additives and your car ends up with a transmission problem, you’ll likely regret your decision.

Many people mistakenly disregard additives to save money. Based on how expensive transmission problems can be, paying a little extra for a transmission additive is worth it in our book.

Conclusion

For most cars, we recommend the Prolong Super Lubricants PSL15000 Transmission Treatment. It is not expensive, and it can prevent several transmission problems. It chemically bonds to metal, which also means it lasts longer than most other additives.

However, for those looking for the absolute cheapest option, we recommend Lucas LUC10009 Transmission Fix. It comes with more applications per bottle and produces a protective film, which helps prevent wear and tear. We highly recommend choosing a transmission additive from our list above, as they have all been checked for effectiveness. Hopefully, one of our reviews stood out to you and proves to be what you need.

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Featured Image Credit: Tim Mossholder, Unsplash