Why You Need Transmission Fluid

By Tiia Monto (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Most people these days are pretty good about changing their engine oil. This is because modern cars come with an engine oil change indicator that tells the car owner when it is time to change the oil. However, transmission fluids are highly neglected for many cars, even though it is just as crucial as changing your engine oil. Transmission fluid is used in automatic transmission cars as a lubricant that keeps it from overheating and helps power the transmission itself. When you do not change your transmission fluid, the transmission will not work correctly and ultimately break down.

Why Are There So Many Different Kinds?

Different car manufacturers have different transmissions. Further, the type of vehicle (ex. SUV vs Sedan) also will require a different fluid even if they are from the same manufacturer. There are a lot of different fluids on the market so it is good to know some of the basics to the most common brands on the market.

Synthetic vs Regular

Regular transmission oil is created by taking crude oil and refining it to the specifications of the car that the oil is specialized for. The refining process focuses on shaping the hydrocarbons to the exact way for a certain transmission. Synthetic oil, on the other hand, is engineered through various chemical reactions from temperature and pressure to make the perfect recipe for your car’s transmission. The components of the oil ends up creating a much more pure compound that is less prone to breakdown, oxidation, and does not thin out from high temperatures. Long story short, this is a rare case where the synthetic product is much better than the organic product.

Common Transmission Fluids


This company produces a few different commonly used oils. One of the most popular fluids on the market is the Dextron II. The Dextron II comes with additives that inhibits oxidation and protects the oil from temperature changes. Another common fluid that Dextron produces is the Dextron III, which is made for transmissions that are more likely to corrode and oxidize. If you have a General Motors vehicle, the odds are high that it uses a Dextron III transmission fluid to lubricate.


This company produces oils that are very similar to Dextron, and a lot of Ford Motor vehicles come with recommendations to use it. Though it is not always the case, Mercon V is usually used on Ford vehicles manufactured after 1997.


ATF stands for Automatic Transmission Fluids. Many companies produce fluids that contains within the fluid name “ATF” so it is important to look at your vehicle manual to pick the correct one. Companies like Castrol, Valvoline, and Mobil are very common brands that use this acronym to name their oils.


Yes, Toyota is the name of a car manufacturer. As the title holder of most cars sold every year, it is important to mention their transmission fluids. Toyota uses Type (insert specific oil descriptor) oils. Again, these oils are similar to the Dextron and Mercon but tailored more specific for the Yota’s

Easy Rule

Take a look at your car’s manual and read how often your car manufacturer recommends you get an oil change. Then, make sure to read the specific transmission fluid that you need to use for your vehicle.

Make sure to keep your transmission properly lubricated. If you simply want your transmission oil changed without the hassle, check out one of AAMCO Colorado’s locations where our specialists can do it for you! If you ever have transmission issues make sure to contact us and our transmission repair experts will get you fixed right up. Drive Safe Colorado.