Tech 101: Type A Automatic Transmission Fluid

If you own a vintage car or you are planning to buy one, you may have noticed that those cars use automatic transmission fluid, called Type A, which is no longer available in the market.

Before buying transmission fluid, you should first identify the recommended fluid for the vehicle. Every transmission requires a specific oil viscosity, additives, and other crucial things. In this article, I’ll explain Type A automatic transmission fluid and its successors. But first, let’s see the common purpose of automatic transmission fluids.

type of automatic transmission fluid

Common Purpose of Automatic Transmission Fluid

The purpose of the transmission fluid is to lubricate and cool the internal transmission parts. Thus, it ensures proper performance, operation, and protection of the transmission unit.

And you need the right fluid for optimum performance. The transmission will not function as expected if you use the wrong fluid. It can put the whole transmission at risk.

The transmission fluid type chart helps you to know the best choice for your vehicle. But why does every gearbox require a different oil grade?

Vehicle transmissions are manufactured by different engineers and with different technologies. There are spaces between intersecting parts. Oil viscosity is mainly chosen to offer a film thickness on the space between intersecting parts at a given load and speed.

Automatic transmission Fluid consists of base oil and different additives. An additive on a fluid may not be compatible with the technology on a certain transmission. Hence, manufacturers recommend fluids that are best suitable for their transmissions.

type a transmission fluid

What is Type A Transmission Fluid

Type A transmission fluid was used in older cars manufactured in the late 1940s to lubricate and cool automatic transmissions. The Type A transmission fluid contains whale oil, which routinely breaks down vehicles at high temperatures.

To prevent the breakdown, newer models don’t use Type A fluid. Starting from the 1970s, manufacturers start producing transmissions that use different versions of transmission fluids. These fluids are eco-friendly in enhancing fuel economy and reducing emissions. Today, it’s difficult to get a type A transmission fluid in the market.

The type A fluid was replaced with the Type “A” suffix “A” fluid. This new fluid can stand higher temperatures caused by newly invented torque converters.

However, the Type A transmission fluid is a Type F transmission fluid equivalent by Ford Motors and Toyota. This fluid was less smooth than type A. However, manufacturers produce Dexron and Mercon fluids to replace Type F.

Other Types of Transmission Fluid

Here is a list of other transmission oils that came into existence after the type A transmission.

Dexron family

Dexron (B) is the first generation of Dexron automatic transmission fluids. They were produced after Type A transmission fluid. When comparing type A transmission fluid vs. Dexron, we find out that Dexron (B) contains more stable and hydrotreated base oil.

It is, therefore, more resistant to heat and anti-oxidation. This fluid is backward compatible with all Type “A” Suffix “A” and the Type “A” fluids produced from 1940 to 1957.

Dexron II: Dexron II was the successor of the Dexron (B). It was developed by GM in the 70s for better viscosity control.  It features additional oxidation inhibitors. It was also the first GM transmission fluid for electronic transmissions.

Dexron III: Dexron III was used to replace Dexron 2. This generation was considered the most successful. It had improved oxidation and corrosion control. Before the year 2000, 80 percent of transmission fluid was covered by General Motors Dexron 3.

Dexron-VI: The success of Dexron continued until 2006, when they introduced Dexron-VI.  The Deron-VI was produced to be used in 6-speed rear-wheel-drive transmissions. Dexron-VI replaced the older types of Dexron B, II, and III. It is a fully synthetic transmission fluid, and the series continues to this day.

Mercon family

The Mercon family started with Mercon-type CJ. It was originally developed for Ford c-6 transmissions. It was developed to compete with GM Dexron 2, which had the same specs.

Mercon V

Mercon type H: It was initially made to comply with Ford spec, which differs from general motors, Dexron, and Ford type f transmission fluids.

Mercon V: Mercon V was introduced in 1997 to serve the new models which require a low-viscosity fluid. It is a quality premium transmission oil recommended by Mercury, Ford, and Lincoln.

Mercon SP: Mercon SP enhanced friction, and it is considered a modified Mercon V model. At that time, every car manufacturer released their specifications of transmission fluid. New types came out, such as HP/J-Matic, which is used by Nissan Transmissions. It is also used in Infiniti and Subaru.

There is also LT7114l, a special formulation for BMW, Diamond SP-II & SP-Ill for Mitsubishi, Hyundai, Kia, T, T-III, and T-IV for Toyota, Lexus, and Scion. There is also a ZL ATF for Honda, except for CVT models.

All the above types of automatic transmission fluids are used for cars equipped with automatic 4/6 speed transmissions. There are other types of transmissions, such as Dual Clutch and CVT transmissions. These transmissions require a specific type of transmission fluid.

Examples of these special grades include full Synthetic CVT Transmission Fluid – SynGard CVT ATF. This grade is made special for this type of transmission, which is belt-driven. The transmissions are very sensitive to the oil grade. Using the wrong oil grade may cause dysfunction on the transmissions and void your warranty.

Can you mix different types of transmission fluid?

It is not okay to mix transmission fluid because most tranny fluids are incompatible with some transmission. Mixing them will cause catastrophic damage to the tranny units. Every transmission needs a specified fluid, as recommended by the manufacturer.

While it is uncommon for someone to mix transmission fluid, car owners often use the wrong transmission fluid type for their vehicles. Using wrong or mixing different transmission fluids will affect the transmission’s operation, performance, and protection.


What is transmission fluid type A?

Transmission fluid type A was used in older model cars produced in the 1940s to cool and lubricate the internal transmission parts. It was used in every car manufactured from 1949 to 1958. After that period, different manufacturers start manufacturing their own transmission oil.

Most importantly, ATF Type A fluid should only be used with recommendations on vehicles that need mineral oil lubrication.

What replaces Type A transmission fluid?

The Type A transmission fluid was later replaced in the late 1950s with the Type A suffix A transmission fluid. The Type A Suffix A was later replaced by Dexron B. Type A and Type A Suffix A transmission fluids are compatible with Dexron B, Dexron II, and Dexron III.

Can I put Type A transmission fluid in my car?

Automakers have recommended fluids for their vehicle transmissions for efficient and smooth running. Most transmission fluids are incompatible with others. Hence, they should not be mixed or used in place of another.

Therefore, if your manufacturer recommends Type A transmission fluid for your car, use it. It will not cause any issues. However, Using Type A ATF fluid on a vehicle that it is not recommended will cause catastrophic damages. In most cases, the damage will only occur in the long term.

What color is ATF Type A?

Manufacturers have dyed several vehicle fluids for easier identification. The ATF type A is no exception. The ATF Type A transmission fluid has a translucent red color.

Is Type A transmission fluid the same as hydraulic fluid?

Type A and other transmission fluids are a form of hydraulic fluid. The purpose of the transmission fluid is to cool and lubricate internal transmission parts.

Final Words

We have got to know the type A automatic transmission fluid and its evolutionary change. Transmission fluids have a big effect on every car. It is something that every car owner should pay attention to. One should also pay attention to the type of fluid that should be used in the car.

If you are not sure, check the transmission fluid compatibility chart. The chart will give you the information you need about the grade. This will help you not to void the warranty of the transmission.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

2 thoughts on “Tech 101: Type A Automatic Transmission Fluid

  1. Hey Richard, thanks for stopping by.

    In general, most vehicles need a transmission fluid change every 30,000 miles and flush every 2 years.

    If the vehicle is up to two years since you bought and the manufacturer recommends type A fluid, flush the system and use any Type A fluid. However, stick to any fluid you chose to use now.

  2. I have a 1966 Oldsmobile Toronado. I changed the leaking transmission cooler lines and will need to add some transmission fluid to the system. It says to use Transmission fluid A. I bought this car two years ago and do not know what fluid is in the transmission. I would assume that using Dextron III would be best. I don’t know if they used synthetic fluid like a Dextron VI. What would you suggest.

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