automatic transmission parts

Is It Really Necessary to Change Your Transmission Fluid?

Most of you probably know the importance of transmission fluid for your automatic transmission, which can ensure your vehicle’s transmission operates at optimal capacity. It is, decidedly, the lifeblood of your transmission that helps with temperature range and rotational speed, lubricates your transmission in order for it to run smoothly, helps seal the different sections in the transmission, and protects the metal surfaces of the transmission from premature wear.

What many people do not know is when they need to change the transmission fluids of their car. Here are some important details that can help you make a more informed decision and prevent an unnecessary trip to the transmission repair shop.

Shelf Life of Transmission Fluid

Just like any other fluid in your vehicle, transmission fluid starts to break down over time from use, heat, and contaminants. If left unattended, transmission fluid will cause slipping issues, shifting problems, and the overheating of your transmission. Now, according to the majority of manufacturers, automatic transmissions call for fresh fluid every 100,000 miles while Honda and Ford recommends you change transmission fluids every 30,000 miles with heavy duty (otherwise, well, never!).

Seems like things have just begun to get complicated. So, let’s take the case where you will need a fluid change every 100,000 miles. Considering that the average driver logs around 12,000 and up to 15,000 miles annually, it will take them more than 6 years (in some cases, almost 9 years) to service their transmission, which is quite a long time when you think about it. It is impossible to predict the condition the fluid will be like in 6 years’ time. This is why it is recommended to get a transmission fluid changed every 30,000 miles or once every couple of years, depending on your driving habits. That way, you can be sure that your transmission will run on healthy fluid at all times, which, ultimately means you will have a more efficient and longer lasting transmission. Plus, you avoid costly repairs from burnt transmission fluids. The truth is that if you do a little search on your own, you will see that the exact time this service should be performed greatly varies by manufacturer. However, it is always better to be safe than sorry.

Important Note: What we mention here is the optimal mileage for fuel change for automatic transmissions.  If your car has a manual transmission, you should consult the owner’s manual and stick to the maintenance schedule you read there.

Heavy-Duty Driving

Transmission fluid change should be done sooner than mentioned above if you use your vehicle in high-stress conditions, such as heavy towing or snow plowing, or if you do hauling or frequent stop-and-go driving. Another factor that affects the condition of your transmission fluid is the climate. If you live in a very hot climate, it is best to have your fluid changed at 15,000 miles or so. This is because 9 out of 10 problems with transmission fluid is overheating. If the operating temperature of the transmission is higher than normal, problems start to present themselves as the transmission fluid degrades much faster than expected. When this happens, it needs to be changed asap to avoid causing mechanical troubles.

Checking Transmission Fluid

A much better way to know if the transmission fluid has to be changed is to check the fluid itself, every month or so. What you need to look at is the quality of the fluid, meaning color, smell, and consistency.

First, warm up the car so that the fluid is under normal operating temperatures when you check it. This will give you more accurate results. That aside, checking the fluid while it is cold might give you a false indication that you have low levels (the fluid expands when it is heated) and think that you need to add fluid. Overfilling the transmission, though, can cause the transmission to act unstable and also cause seals to blow.

So, start your car in Park or Neutral, let it run for a few minutes, and then remove the dipstick from the cylinder. Use a towel to wipe it down and take note of the:

Color – If it is bright red and transparent, then it is all good. A darker red to light brown is also normal for running vehicles while a dark brown color means immediate fluid change. Finally, a black color is the last thing you need to see as it means that your transmission is already having problems.

Smell – New fluid usually has no smell at all. So, if your transmission fluid gives off a burnt smell, it means trouble and you need to get the car serviced the soonest possible.

Consistency – Fluid that is clear of any contaminants (i.e. metal shavings) is healthy. In any other case (i.e. fluid that is foamy or has contaminants) you should consider changing the fluid (most likely you are using the wrong fluid) or check your gears and torque converter.

Flush Transmission Fluid or Not?

Many repair shops prefer to force out the old transmission fluid and pump in new. Whether you should agree to flush systems, though, is a controversial topic. Some manufacturers, like Honda, suggest you don’t do this for several reasons. One is because automatic transmissions have filters that should be either replaced or cleaned every time the fluid is changed. Plus, using the wrong fluid could cause damage. So, always consult your manufacturer’s instructions and make sure the repair facility you visit uses the right procedures and type of fluid for your vehicle.

What to do if your Vehicle Has More Than 1000,000 Miles

If your vehicle has more than 100,000 on the odometer and you have never changed its transmission fluid, it is strongly suggested to add fresh fluid, especially if you are planning to keep it for a few more years. You may hear mechanics claiming that if the vehicle has no transmission-related problems, you should leave it well alone to avoid transmission failure. There is no evidence, as of now, that shows such a thing can happen or, at least, happen often, so it is best to just follow the manufacturer’s recommendations.