Your car's transmission fluid is to your transmission as engine oil is to your engine. It cleans, cools, protects, and facilitates movement among the transmission's internal workings. But transmission fluid doesn't last forever; like engine oil, it deteriorates over time. The deterioration process can also be sped up by hard driving (including city driving, towing, hauling heavy loads, driving in hot weather, dusty atmospheric conditions, and so on). But unlike engine oil, transmission fluid doesn't have a clear-cut changing interval. Here are three ways you can determine when it's time to change the fluid.
1. Manufacturer recommendation
Different auto manufacturers offer different recommendations for transmission fluid changing. So depending on your car, you may need to change the fluid at a longer or shorter interval. Check your owner's manual for the recommended interval between changes.
2. Smell and appearance
Transmission fluid generally starts out life red. However, as it deteriorates, the shade of red tends to change. If you're going to use the color as an indication of when you should change the fluid, you'll need to have a reference point to compare its current color to. For this reason, using the color as an indicator works best if you saw the fluid when it was new. A color several shades darker than the original may mean it's time for a change. If you can see contaminants (such as dust particles) or smell a burned odor as well as noting a color change, you can be fairly sure the fluid's lifespan is up.
3. Shifting problems
Sometimes a problem with transmission fluid will translate into a problem with shifting. Of course, there are many other reasons why you could be having problems shifting. Another component of the auto transmission could be worn out or damaged. In fact, another component of the transmission could be damaged because the transmission fluid is old and not doing its job. But if the shifting feels just a bit off, the first thing to try is changing the transmission fluid. If that fixes the problem, it was an easy fix. If not, it narrows down the possibilities and makes diagnosing the problem easier.
These three signs are just a general guideline to help you determine when your transmission fluid needs changing. If you're unsure about your interpretation of the signs, you can ask your mechanic for a professional opinion on the condition of your transmission fluid.