Transmission Fluid: What You Should Know

Your car’s transmission — and the fluid that keeps it working — can be a mystery. Add some clarity to transmission fluid with this guide covering everything from maintenance best practices to how to spot signs of trouble.

AAMCO  | 07/16/2020
Vehicle Maintenance

What Is Transmission Fluid?

You have likely heard of transmission fluid, but have you ever taken the time to understand what the chemical concoction is, and what it is does under the hood? 

While both automatic and manual transmission vehicles utilize transmission fluid, the most commonly used fluid is Automatic Transmission Fluid (ATF). ATF is typically manufactured with a refined mixture of base oil and a combination of additives. These additives work with the oil to create the proper lubrication needed for many essential mechanical elements throughout the car. 

The transmission itself is much more than a single component in your vehicle. An average transmission contains many interlocking parts that must remain fully lubricated to avoid particle buildup and dryness that can lead to grinding, overheating, or breakage. 

The chemical compounds in ATF will not only keep your transmission components cooled off while driving but will also keep each element fully functional over the lifetime of your vehicle. The last thing you need is to replace your transmission — a costly repair that could severely impact your wallet.

Signs You May Need A Transmission Fluid Change

If you are facing car transmission issues of any kind, you should immediately check your transmission fluid levels and quality. Many of the most common issues related to the transmission can be traced back to a lack of the proper amount of liquid or the right quality of ATF in the automobile. 

While some vehicles have a transmission fluid dipstick to measure the fluid levels, many newer vehicles are doing away with the stick for electric, dashboard-based notifications. Part of the reason for this evolution is that proper transmission fluid care takes more than an eye on a level or a color, as ATF and engine fluid are very different chemicals. Another element is the increasing use of “lifetime” synthetic ATF options that may not don’t need servicing as frequently as older petroleum-based fluids. 

Common signs that you may need to address your car’s transmission fluid can include:

  • Transmission won’t engage or stay in gear while driving
  • You notice a consistent shift delay or a jumping of gears
  • The transmission feels to be “slipping” or the engine is revving high without shifting
  • Transmission fluid is leaking from the engine block
  • You notice a burning smell or a humming/buzzing noise within the vehicle
  • The car has lost power or will not operate
  • The appearance of either “Check Engine” light or Transmission Temperature light 

How Often Should I Change My Transmission Fluid?

First and foremost, become familiar with your car’s manufacturer-provided owner’s manual. The manual will give you the most accurate guidance for how often you should change the transmission fluid, which type of fluid to use with the vehicle, and other information that may be pertinent to your vehicle.

Many experts generally recommend a transmission fluid replacement every 45,000 to 80,000 miles depending on your driving behaviors. When your vehicle is used in hot or cold climates, hilly terrain, stop and go traffic, to tow or carry heavy loads, or if you plan on keeping your vehicle for mileage more than 100,000 miles, you will want to change your fluid and change it more often in order to keep it clean and fresh even if you use a synthetic “lifetime” marketed transmission fluid. A transmission professional or car inspection can help you get an idea as to the current state of your transmission fluid, any issues related to the transmission, and help inform you what is the best course of action for your vehicle. All vehicle owners should make sure to add transmission fluid checks to your regular maintenance. 

What is the Difference Between a Transmission Flush and a Fluid Change?

There is can be some confusion related to the difference between a transmission flush and a fluid change. A transmission fluid change is simply removing the dirty fluid from the transmission pan and replacing it with a new product while leaving some of the old fluid in the pan. A flush completely removes almost all ATF from the vehicle and fully replaces the fluid throughout every element of the transmission and cooler.

A transmission flush is completely safe for your vehicle when completed by a qualified professional. However, a transmission flush is not a guaranteed fix for major or even some minor transmission issues.

Leave It To The (Transmission) Experts

When it comes to your transmission, you should always employ the services of a trained and experienced transmission professional before making any decisions. AAMCO centers have years of experience servicing transmissions across various vehicles, a transmission technician can quickly and effectively help you with nearly any transmission fluid issue — from a simple check to a full fluid flush. 

A transmission expert can also diagnose and help you understand any symptoms your transmission is showing, and help you make an informed decision about how to best alleviate the problem.

Adding an understanding of transmissions to your automotive knowledge can help avoid costly problems down the road. As with all automotive related upkeep, regular maintenance is the best approach.  If you keep an eye on your ATF, you can take one more car-related worry off your mind and get back to enjoying the freedom of driving!

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