Best Transmission Additives

10 Best Transmission Additives of 2022 – Review and Buying Guide

Regular oil changes are important for keeping vehicles performing at their best, but many people neglect their transmissions. Transmission fluid is not changed regularly like engine oil, and a transmission flush is more expensive than an oil change.

A transmission fluid flush also requires a costly machine that prevents most owners from changing their own fluid. As a result, many drivers forget to service the transmission fluid with any regularity, while others avoid doing so due to its cost.

Neglecting to change your transmission fluid poses the same problem as not changing your engine oil. As the transmission fluid ages, it breaks down and doesn’t lubricate as well. The internal workings of the transmission wear out faster as a result.

As the fluid breaks down and the parts begin to wear at a faster rate, the fluid becomes dirtier, which causes even more wear. Fortunately, there are many products on the market that can help to extend the life of your transmission and transmission fluid.

Top 5 Transmission Additives: Editor Recommended

In addition to improving lubrication, these additives remove dirt deposits and refresh seals. But which is best on the market? We’ll discuss the best transmission fluid additives here, as well as what they are and why you might need them.

Refer to our table of contents for more information on the best transmission fluid additives.

Types of Transmission Additives


The manual gear system consists of two shafts with gears each. These gears mesh together after the user engages the clutch and gearstick. In this way, the manual transmission system creates a great deal of heat, friction, and force when the two moving objects collide. Thus, manual transmission fluid, as well as additives, must prevent damage to components as the gears shift smoothly. In order to achieve this, manual transmission fluids have a high viscosity, can endure extreme pressures, and are heat resistant.


Transmissions operate on a planetary basis. The gearbox automatically shifts gears according to engine demands. An automatic gearbox tends to be smaller and have more moving parts than a manual gearbox. Automatic transmission fluid, as well as additives, are on a different level than manual gearbox fluid. Heat-resistant additives for automatic transmissions have low viscosity and anti-foaming properties.

The 10 Best Transmission Additives Review:

1. Lucas LUC10009 Transmission Fix 24 oz., Brown

Lucas LUC10009 Transmission
  • Lucas Transmission Fix Stops Slip, Hesitation, Rough Shifting In Worn...
  • Fit Type: Universal
  • Can be added to existing fluid without draining any out
  • Improves shifting

Lucas has been a leader in engine oil additives for years, so it comes as no surprise that the company also provides transmission fluid additives. This product does it all, you just add the thick fluid to your transmission fluid to make it work. Lucas transmission fluid does not need to be drained; simply add it to the current fluid and let it do its magic.

Lucas Transmission Fix prevents slipping, hesitation, and rough shifts. To accomplish this, it provides all of the components with a thick layer of protective coating. The thick fluid enhances shifting by lubricating the transmission valve body.

Lucas’ product also refreshes shift bands, preventing slippage under power. This recommendation also protects your transmission’s moving parts while preventing fluid leaks. Transmission fluid is thinner than motor oil, and as it breaks down, it becomes even thinner.

Because of this, the vehicle’s battery drains down faster when not being used, resulting in metal-to-metal contact at startup. Lucas Transmission Fix prevents lubricant from draining down, protecting the metal surfaces on start-up. In addition, this transmission additive rejuvenates worn gaskets and seals, preventing leaks.

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2. Prolong Super Lubricants PSL15000 Transmission Treatment

Prolong Super Lubricants PSL15000
  • Includes a Formula with Anti-Friction Metal Treatment Technology
  • Features Engineering Designed to Treat Metal Surfaces Through a Molecular and...
  • Offers Molecules that Interact with Metal Surfaces and Chemically Bond to Create...
  • Offers to Treat the Metal Surfaces of Both Standard (Manual) and Automatic...
  • Features a Formula that Promotes Smoother Manual Shifts and Helps Restore...

One of the best and most popular transmission additives on the market is Prolong Super Lubricants PSL15000. Automatic and manual transmissions can both benefit from this additive. Molecular interaction takes place between Prolong Super Lubricant and metal surfaces. In the transmission system, these molecules create a protective layer that reduces friction and heat.

The PSL15000 promotes smooth and responsive gear changes, and it can be used on both high- and low-mileage vehicles. With one bottle of Prolong Super Lubricants, one transmission will be treated. It contains AFMT, which chemically bonds to the surfaces of your system, which helps prevent wear and tear.

This product has the drawback of not being designed to work with CVT transmissions. SUVs and trucks with high mileage are not as effective with this product.

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3. CD 2 Marvel Mystery Oil MM12R

Marvel Mystery Oil MM12R
  • For best performance, follow the manufacturer's recommendations in your vehicle...

Marvel Mystery Oil, dubbed “the original oil enhancer and fuel additive,” will also benefit your automatic transmission. Upon addition to the transmission, the product rids the lubrication system of sludge and debris. The sludge in your transmission causes parts of the valve body to malfunction. The valve body will lead to sluggish or rough shifts when it isn’t functioning correctly. Depending on where the unwanted deposits are located, the flow of transmission fluid can be altered, causing accelerated wear and costly damage.

The Marvel Mystery Oil will clean out the debris on your valve body bits so your valves will move smoothly, reducing friction and heat. Afterwards, it bonds to the internal surfaces, protecting them from future build-up. In addition, this reduces friction and heat, allowing your transmission to work for a longer period of time.

Its key advantage is the fact you can put it in your engine oil, fuel system, or power steering system. As a fuel system cleaner, it offers similar advantages to the engine oil and power steering fluid.

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4. Hot Shot’s Secret – HSSTSE32Z Shift Restore Automatic Transmission Additive

HSSTSE32Z Shift Restore Automatic Transmission
  • Hot Shot's Secret Shift Restore is engineered to safely dissolve the harmful gum...
  • Reduces transmission operating temperatures with high performance ester formula
  • Our Shift Restore formula acts as a high-quality transmission lubricant that...
  • Shift Restore's formula is designed to instantly attach itself to all of your...
  • Reduces transmission wear, erratic and inconsistent shifting, hesitation and...

Hot Shot’s Secret HSSTSE32Z might be the best option for diesel engines without suitable transmission additives. This ATF additive is suitable for gas and diesel automatic transmissions. Transmission additive that softens shifts, creates a smoother ride, and protects transmissions.

As a result, the HSSTSE32Z lowers ATF temperatures, reduces friction, and eliminates rust and corrosion, improving the performance of your automatic transmission. The Hot Shot’s Secret Transmission Additive is compatible with CVT transmissions as well. This lubricant is highly formulation and has a composition capable of removing deposits.

The HSSTSE32Z is made for automatic transmission vehicles only, which is a major drawback. It is also expensive compared to other transmission additives. However, the 32-ounce bottle gives you a greater benefit.

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5. Bar’s Leaks 1400 Transmission Repair

Bar's Leaks Transmission Repair
  • Restores performance
  • Stops slipping and prevents lazy shifts
  • Quiets noise
  • Stops leaks
  • Conditions seals and o-rings

It is manufactured by one of the most well-known brands of automotive additives. Bar’s Leaks has been around for a long time, and it offers a product for just about every fluid on your vehicle. This transmission additive is also packaged as a two-in-one product. On one side of the bottle is a product that promises to restore performance. On the other side of the split bottle, it states that it adds protection.

The Bar’s Leak transmission additive cleans out the valve body and the area around the gears to restore performance. Proper fluid flow prevents hard shifts and slipping. Additionally, it improves the condition of the shift bands, along with various gaskets and seals. The bottle guarantees that this product will prevent leaks, which makes sense for a brand known for preventing leaks. All of their products have been proven to work.

The other half of the bottle contains a fluid that stabilizes the existing transmission fluid while coating all moving parts. As a result of this layer, friction and heat are reduced, improving performance and adding to transmission longevity. Also, periodic transmission service will prevent transmission fluid from breaking down as quickly.

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6. Lubegard 63010 Platinum Universal ATF Protectant

Platinum Universal ATF Protectant
  • The Original Universal ATF Protectant that Eliminates ATF Confusion and the need...
  • Will not alter the crucial sulfur balance in your transmission fluid, Prevents...
  • Contains patented Synergol TMS Technology, a synthetic molecule that tightens...
  • Extends fluid change intervals, Protects and restores seals for optimum...
  • Does not contain any harmful components such as zinc (ZDDP)/ash, etc., like...

Lubegard is a budget-friendly and reliable transmission fluid that you can use with automatic transmission fluids. The product reduces friction and protects metal parts and internal components from damage. Furthermore, the additive prevents transmission overheating without damaging it.

The Synergol TMS Technology in the additive eliminates shudder and noise, making your ride more enjoyable. Another great feature of this additive is its ability to protect, condition, and restore seals and O-rings. Changing the transmission fluid is also delayed, which is convenient. Lubegard ATF protectant is one of the favorite choices among mechanics and drivers for all the reasons mentioned above. Another reason might be that it is compatible with most automatic transmissions.

Despite the claims of universality, the additive will not work on just any type of vehicle. CVT transmissions, such as those found in new cars and older Fords, will not be able to handle it. The company’s website provides a comparison chart that will help you determine whether the product is compatible with your system.

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7. Sea Foam Trans Tune TT16

Sea Foam Trans Tune
  • Helps fluid systems work smoother and last longer
  • Dissolves and liquefies harmful gum and varnish buildup in fluid
  • Cleans and lubricates valve bodies, shift actuators and solenoids, controls...
  • Safe in most types of automatic transmission fluid, hydraulics, or power...
  • Safe for conventional and synthetic fluids

Sea Foam is a well-known solution to a rough-running engine, but the company can also assist with transmission problems. Sea Foam Trans Tune may be the answer if you have concerns about your transmission shifting improperly and your fluid looking dirty. A first step in using this product is to loosen any buildup of debris around the valve body and gear. Smoother shifts and fewer gear hang-ups are the results of a clean valve body. As well as cleaning and conditioning the transmission fluid, the Sea Foam also removes moisture from the system and disintegrates any accumulated debris.

The two methods for using Sea Foam Trans Tune are as follows. This product can be added to transmission fluid 100 miles before the service is performed if you are getting ready to have your transmission flushed. Clearing out the system should be your primary concern. The Sea Foam will loosen up all the crud in your transmission, making the flush process much easier.

By adding Sea Foam to the new fluid, you can help keep debris from accumulating in your transmission in the future.

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8. XADO EX120 Revitalizant for Manual Transmission

Revitalizant for Manual Transmission
  • Repairs Scratches and Damaged Working Surfaces - Improves Operation Of...
  • Increases Gear Contact Efficiency - Resulting in Better Gear Shifting Accuracy
  • Works with Manual & Direct shift, Robotized Gear Boxes, Transfer Cases &...
  • Reduces Noise And Vibrations. Stops Slipping and Hard Shifting
  • If There Is a Heavy Transmission Fluid Leakage - Transmission Will Still Work Up...

A product like this solves many transmission issues. In addition to reducing noise and vibrations, the additive also helps to prevent hard shifting and ensure smooth transmission operation. We find it quite effective in manual systems and some buyers even use it in CVT transmissions without any problems.

One of the best things about this product is its versatility. Rebuilds, repairs, and protects metal and internal transmission parts with XADO EX120 Revitalizant. A single application of this product will last for 62,000 miles, which is quite impressive. Moreover, a tube with the gel along with a syringe will be included for easy application.

Depending on how the product works, you might have to wait. Transmission issues can sometimes take time to resolve. It may even take several additions of the product before any changes are noticed. We recommend looking at other options on our list if you require a product that will work instantly.

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9. ATP AT-222 Trans Fluid Additive

Trans Fluid Additive
  • Product type :AUTO ACCESSORY
  • Package dimensions :14.986 cm L x18.034 cm W x11.684 cm H
  • Short Description : Trans Fluid Additive
  • Automotive paints and primers

ATP AT-222 Trans Fluid Additive can help eliminate your transmission’s new habit of shuddering. Specifically, this product is formulated to deal with problem transmissions. It’s a highly concentrated additive that acts as a synthetic friction modifier, preventing the torque converter’s potential shuddering. Thanks to the highly concentrated ingredients, you’ll be able to solve your problems quickly. All make and models of automatic transmissions are compatible with this quick-working, super-concentrated additive.

However, there are some drawbacks to its formula. In contrast to more general products, this specific transmission additive contains no enhancements. Transmitter heat won’t go down, wear will go down, nor will transmission fluid last longer. In other words, it’s merely meant to provide a solution, not a general salve.

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10. K & W Chemical Trans-X High Mileage Automatic Transmission Treatment

High Mileage Automatic Transmission Treatment
  • K&W SEALANTS & SOLUTIONS: From head gaskets and engine blocks to automatic...
  • TRANS-X LEAK REPAIR FLUID: Specially developed for vehicles with 75,000 miles or...
  • APPLICATION RANGE: Our leak stop fluid is formulated to prevent and restore...
  • SAFE HANDLING: Highly flammable transmission stop slip must be stored in a...
  • PRODUCT SPECIFICATIONS: Trans-X High Mileage Transmission Fluid is available...

Consider K & W Chemical Trans-X High Mileage Automatic Transmission Treatment if you drive an older car with many, many miles on the odometer. For cars with 70,000 miles or more, this transmission additive was specifically formulated and designed for use in high mileage vehicles as well. With each 16-ounce container of this additive, you can extend the life of your current transmission, avoiding common problems that are caused by a lot of driving.

The high-tech formula in this transmission additive is designed to protect and strengthen transmissions, preventing leaks before they happen. This option is also excellent if you notice that your vehicle no longer shifts smoothly; it can restore it. This can also help replace any depleted ingredients your transmission fluid has lost over time.

It’s important to keep in mind that this additive is best used if you are just starting to experience transmission issues like slips and shudders. Having persistent problems will render it ineffective.

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Buying Guide: What to Consider When Choose a Transmission Additives

Transmission Additives

  • Transmission conditioners are usually recommended for use with existing transmission fluid. It is, however, recommended that you check the fluid level first. Overfilling could lead to damage.
  • In order to add a transmission additive, you must first warm up the engine and transmission of your vehicle. Idle your vehicle for at least 20 minutes before adding the additive.
  • Be sure to read the instructions on the additive before adding it to your system. Some additives may only require one bottle. A larger vehicle, however, might require two.
  • Make sure you locate the correct dipstick before adding transmission additive. Check your vehicle’s owner’s manual or online if you are unsure where it is located. Pour the additive through a funnel after you remove the dipstick.
  • Driving your vehicle and shifting through the gears for a while after adding the additive is recommended.

Frequently Asked Questions

i) Can I Add Transmission Additive Myself?

The DIY approach is certainly an option. Just be sure to locate the transmission dipstick. A couple of minutes of preparation can help you complete this task. The additive instructions and the vehicle owner’s manual should be read carefully.

ii) When Is It Ideal to Use Transmission Additive?

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The best time to use transmission additives is when you’re experiencing transmission slippage, stalling, rough shifting, or seal leaks, and you’d like to try an alternative to a repair shop.

iii) Should I Add a Transmission Additive When Changing Transmission Fluid?

Adding transmission treatment is not recommended unless you have been experiencing difficulty shifting, slipping, or hesitation.

iv) Do Transmission Additives Really Work?

Answering this question depends on a few factors. A transmission additive formulated to target those problems can be effective if you’re experiencing problems with your transmission. Depending on what kind of additive you use and whether your car is old enough or not, you may not really notice a difference in performance. Some additives can actually damage transmission fluid, so make sure to thoroughly research anything you add to it.

v) What Transmission Additives Work for Slipping?

When your transmission slips, you should use an additive that is designed specifically for this problem. Some products are formulated to clean your transmission and its components, while others are designed to target specific issues, such as slipping and shuddering. Concentrated formulas can work quickly, but double-check the label to make sure that is the case with the additive you select.

Final Thoughts

Prolong Super Lubricants PSL15000 is our pick for the best transmission additive. It is one of the best transmission additives available. The filter reduces leaks, shudders, slippages, and sludge buildup.

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