How Do I Know Which Transmission Fluid is Best for My Gearbox? MILTA Technology

How Do I Know Which Transmission Fluid is Best for My Gearbox?

Way back when, it seemed there were essentially only two types of automatic transmission fluid (ATF), Type A and Type F. The latter was for Ford cars, and the former for all the others. Times have moved on and now the list of transmission fluids has grown.

But how can you know for sure which is the right transmission fluid for your car? Isn’t it all essentially the same stuff just bottled in differently branded containers? In today’s blog we seek an answer to this question and more.

Background: Broad Strokes – Types of Automatic Transmission Fluid

Type F

This may be the very oldest type of transmission fluid on the list, but it’s still around and used in a number of cars, especially classic cars from the 1970s. Type F transmission fluid was designed initially for Ford cars that made use of bronze clutches, which in general haven’t been around since the 1970s. If your car isn’t a classic, then chances are that it isn’t using Type F fluid.

Dexron / Mercon

The next type of fluid is any made by either Dexron or Mercon. These two names are synonymous with virtually all automatic transmission fluids that are available on the market nowadays. The fluids are usually numbered using Roman numerals, so it might show as “Dexron III” for example. If you check your owner’s manual, it most likely recommends one of the Dexron or Mercon fluids, perhaps even saying that any number fluid will do.

If your manual or mechanic says that any type of Dexron or Mercon is alright in your car, then you can take this as fact. Many of the largest car manufacturers like GM, Ford and others do use these fluids. However, if the manual specifies one in particular, then that’s the one you should use. If the manual specifies that you should use Dexron III, for example, but your mechanic says any will do, then bring up what the manual says to be sure.

Highly Friction Modified

Highly Friction Modified (HFM) transmission fluids are those that are a little more modern and advanced. They are engineered to provide different characteristics in their friction compared to Dexron or Mercon fluids. Many popular OEMs that are widely known in the UK make use of these HFM fluids, including Honda/Acura, Hyundai, Toyota/Lexus, and Jeep.

HFM fluids typically feature increased resistance to things like cold, heat and oxidation. This helps them to last longer in the same way that synthetic engine oil lasts much longer than conventional oil. Where you might have to take conventional transmission fluid and change it after 30,000 or 40,000 miles, an improved synthetic version might last well over 60,000 miles or even up to 100,000 miles in some cases.

Automatic Vs. Manual Transmission Fluid

Automatic transmission fluid (ATF) is specially formulated to deliver greater heat resistance, thermal stability and great reduction in friction between the moving parts. It also has to inevitably deal with greater pressures, and requires more stability in its viscosity to work properly. ATF is typically a rich red or dark pink in colour when new, but will change to a dirtier brown/orange colour over time.

Manual transmission fluid (MTF) is more like engine oil in its appearance, and shows as brown or amber in colour when fresh. It will also degrade over time like ATF does, and like engine oil does. The main functions of MTF are to keep gears shifting smoothly, and to reduce wear and tear on the “carrying components” that ensure the system stays synchronised and functional.

CVT Fluid

Continuously variable transmissions (CVTs) are another kind of automatic transmission, but they too require a different fluid. If your car is a CVT, then you need to check the packaging of transmission fluid for those that say they are CVT-specific. Regular ATF is not right for your CVT gearbox. There is some confusion because some brands, such as Castrol, use red as the colour for their CVT fluid, which makes it appear the same as other ATF. In fact, there is no standard colour for CVT fluid, so other brands will come in different colours. Therefore, look for the CVT label on the packaging.

How to Know Which Transmission Fluid is Right

To wrap up, let’s go through some of the key ways in which you can know for sure which transmission fluid is right for you and your car.

1. Ask Your Mechanic

If your mechanic knows his/her stuff, then they will know which transmission fluid is right for your particular vehicle. Be wary of any mechanic that is trying to push an expensive brand at you as a replacement for what you know you used previously. If you stick with OEM-specific mechanics, you shouldn’t run into this problem.

2. Check Your Owner’s Manual

The other key place to check for the right transmission fluid is your owner’s manual. It should specify quite clearly what fluid is recommended. It’s not to say that no other fluid will do other than the one recommended by the manufacturer, since new fluids may emerge since the production of your car that are eminently suitable. However, sticking with the OEM-recommended fluid remains the safest choice.

3. Look for Your Car’s Brand on the Fluid Container

If you’re shopping for transmission fluid yourself, you’ll likely find that many products list specific car brands on the bottles or other containers in which the fluid comes in. Japanese brand cars are particularly known for this, like Honda and Toyota.

4. Ask Your Mechanic

Yes, we’re repeating this point one more time. Your regular mechanic is still the best person to check with when it comes to getting replacement transmission fluid. If you spot new products and are interested in trying them, share the idea with your mechanic and see what they say.

Conclusion: Never Ignore Your Transmission Fluid

In the end, we can’t escape the importance of maintaining healthy transmission fluid in our cars. Just as the oil is the lifeblood of the engine, the transmission fluid is the lifeblood of the gearbox and surrounding systems. When that fluid is not working at its best, neither is your transmission, and thus by extension neither is your vehicle.

The consequences of skipping transmission fluid checks, or using the wrong kind of fluid that’s unsuited to your particular car include (but are not limited to):

  • Transmission overheating
  • Increased premature wear and tear
  • Damage to the clutch and connected gears
  • Expensive repairs
  • Even more expensive transmission replacement

Does saving a little cash on skipping a transmission fluid flush and change make up for the elevated cost of these consequences? We think not. If you’re unsure about anything to do with your transmission fluid, ask your mechanic to tell you more about it. At the same time, do as much as you can to learn about how to check your transmission fluid using the dipstick in your car (if it has one), or how to read the signs of bad transmission fluid if you don’t have a dipstick.

A healthy transmission invariably means a healthy and roadworthy car.

Write a Comment