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What should you know about transmission fluid

Your car's transmission fluid is an oily liquid that primarily functions as a lubricant for the parts inside of the transmission. In cars with automatic transmissions, the fluid also does the job of a coolant, helps to transmit power from the engine to the car's transmission, cleans and protects metal surfaces, and conditions gaskets.

Automatic transmissions use Automatic Transmission Fluid or ATF which is really a special type of oil. A variety of oils can be used with manual transmissions — regular motor oil, ATF, or even a heavyweight gear oil. Transmission fluid is very specialized, and the type that you use in your car depends upon its make and model and automatic vs. manual transmission. You need to consult your owner's manual regarding the type of transmission fluid that is recommended by the manufacturer.

Because the transmission fluid plays so many vital roles in keeping your car in good running condition, it's important to check the level of transmission fluid at regular intervals. Letting the fluid level run low can cause major problems with the internal workings of your car's transmission, resulting in costly repairs.

Types of transmission fluids

The first rule of thumb in determining the type of fluid that is right for you car in order to achieve optimal performance is to consult your owner's manual. The manual lists ATF specifications that are recommended by your car's manufacturer.

Dexron/Mercon are the (2) commonly used ATF's today. Dexron was originally developed by GM, with Dexron-VI being the latest grade. Mercon was introduced by Ford Motors in 1987 with the most common grade being Mercon V. Most GM and Ford vehicles use this type of ATF as do many imports.

HIghly Friction Modified or HFM-Style Fluids are similar to Dexron and Mercon, but with enhanced friction modifiers. They are marketed under a number of different names, including Chrysler ATF +4, a synthetic oil introduced in 1998. HFM's are used by a number of manufacturers including:


Type F is a old ATF introduced by Ford in 1967 and is used in older model Fords ( prior to 1977) and some older makes and models of imports.

Should I do my own transmission fluid replacement?

Whether you car has a manual or automatic transmission, it's good practice to let a certified mechanic flush and change your car's transmission fluid. Most shops that specialize in transmission service and repair, such as Transmasters Transmissions and Auto Care, are equipped with a transmission flusher that can more thoroughly replace the fluid and ensure that all of the dirt and debris that have accumulated over time can be removed before adding new fluid.

Transmasters has been in the transmission repair and servicing business for over 24 years. Our staff of ASE-certified mechanics are up-to-date on the latest technology in transmission service. Visit our website to read reviews from many of our satisfied customers.

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