Sergeant Clutch Certified Engine & Transmission Shop

6557 Walzem Road San Antonio, Texas 78239 Call 210-239-1600
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What Type of Automatic Transmission Fluid Should I Use?


FAQs Automatic Transmission, Transmission Problems, Automatic Transaxle, San Antonio Transmission Repair Shop


Automatic transmissions use a special type of oil, called Automatic Transmission Fluid, or ATF. This fluid has a number of duties in the automatic transmission, including lubrication, cooling and clutch application. Automatic transmission fluid provides the connection between the engine and transmission, through a hydraulic coupling called a torque converter. And, when squeezed between the clutches, automatic transmission fluid acts as a “glue,” providing additional friction and holding capacity to drive the car or truck. So automatic transmission fluid is a very versatile fluid. That’s why maintaining the transmission fluid can be so critical to an automatic transmission life.

Just a few years ago there were only two types of automatic transmission fluid on the market Type A and Type F. Conventional wisdom said that Type F transmission fluid was for all Ford transmissions and Type A was for all other transmissions. Conventional wisdom wasn’t all that accurate even back then. These days there are four main types of automatic transmission fluids on the market. And there are dozens of brands and styles to choose from. There are many different types of transmission fluid on the market, and using the wrong type can affect your automatic transmission’s performance and longevity.

So how do you know what type of transmission fluid your car or truck uses? The easiest way to make sure you’re using the right type of automatic transmission fluid is to check the vehicles owner’s manual. It’ll tell you exactly which Transmission Fluid the manufacturer recommends for your car or truck. May times on the transmission dipstick will indicate what type of ATF to use.

Automatic Transmission Fluid Types

Here’s a list of the different types of automatic transmission fluids and the basic differences between them:

1. Type F Automatic Transmission Fluid: Almost no automatic transmission uses Type F anymore. Type F was designed for Ford transmissions that used bronze clutches. The last automatic transmission made with bronze clutches was the Cruiseomatic, last used in the early ‘70s. Unless you’re talking about a classic car or an antique, you can be pretty sure your automatic transmission doesn’t use Type F.

2. Dexron III / Mercon Automatic Transmission Fluid: This is one of the most common automatic transmission fluids on the market. Most GM transmissions and Ford transmissions, as well as many import transmissions, use this type of ATF. If your vehicles owners manual recommends any form of Dexron or Mercon other than Mercon V this is the transmission fluid you want to use.

3. HFM-Style Automatic Transmission Fluids: HFM stands for Highly Friction Modified; it’s an automatic transmission fluid that provides different friction characteristics than Dexron III / Mercon. This transmission fluid appears under a number of different names, including Chrysler’s ATF+ also called 7670. Many other manufacturers use HFM ATF these include: Honda Transmissions, Acura Transmissions, Jeep Transmissions, Eagle Transmissions. Hyundai Transmissions, Toyota Transmissions, Lexus Transmissions, Saturn Transmissions and Sterling Transmissions.

Are HFM fluids interchangeable?

They should be. But to be safe, always use the specific transmission fluid the vehicles manufacturer calls for.

4. Automatic Synthetic Transmission Fluids: A number of automobile manufacturers have begun to discontinue the use of organically based transmission fluids in favor of synthetic transmission fluids. Preliminary tests have shown that most synthetics have similar friction modification characteristics to Dexron III/Mercon transmission fluid, but with improved resistance to heat, cold, oxidation, sheer and synthetic fluid last longer.

Automatic synthetic transmission fluid is one reason why many automobile manufacturers begin to eliminate the automatic transmission dipstick. Manufacturers feel synthetic transmission fluid will last longer, so there’s no reason to let people interfere with the automatic transmission and its operation.

Caution Ford labels their automatic synthetic transmission fluid as Mercon V, which can be a bit confusing. If the vehicles owner manual says Mercon V, it’s calling for the synthetic transmission fluid. If the name is Mercon without the V, that’s the regular Dexron III/Mercon transmission fluid.

Still not sure which fluid you need? Stop by Sergeant Clutch Discount Transmission Repair Shop and our transmission mechanic will be happy to check your vehicles transmission fluid. Call today 210-239-1600 to schedule an appointment or visit us at 6557 Walzem Rd. San Antonio, Texas 78239.