Transmission Fluid Changes Colors As it Ages

What color is transmission fluid? The answer is red. Bright red, to be exact. As it ages, however, transmission fluid changes color, which is why mechanics take into account the color of the fluid during a transmission inspection and service. This fluid, or oil as some people refer to it, is very important. It protects the transmission from heat, dirt, and wear and tear much like motor oil protects your engine, but it also helps the transmission each time it shifts gears. CAR FIX Cookeville can make sure your vehicle’s transmission fluid is always clean and fresh. Let’s talk about how it colors as it ages.

New Is Red

As we said above, new transmission oil is bright red. It is sometimes confused with power steering fluid, which is also red. Your vehicle’s engine coolant might be red, as well, so it’s important to understand where transmission fluid might leak from your automobile. If you have red fluid leaking from the front of your car, truck, or SUV, it’s probably power steering fluid or coolant. If it’s leaking from the center of the vehicle, it’s transmission oil. The fluid is also see-through and slick when it is new.

Aging Is Brown

A couple of things start to happen to transmission fluid as it gets older. Transmission fluid is entirely encased in the transmission, so dirt and grime aren’t what generally starts to turn it brown. Rather, heat changes the color of the transmission fluid. Over the span of about 30,000 miles, your transmission will go from red to light brown, and this is because the fluid is thickening a bit and starting to oxidize from constantly circulating through the transmission to draw heat away from the parts.

As long as the fluid is light brown, you don’t need to worry about changing it just yet. Again, at about 30,000 miles, however, your transmission fluid might be brown, and now you must change it. Keeping the brown fluid in the transmission will continue to oxidize the fluid, rendering it incapable of lubricating moving parts, protecting them from heat, and helping the transmission gears function. Continuing to drive with dark brown or black transmission fluid will cause irreparable damage.

You can prevent this from happening by scheduling a transmission service with CAR FIX Cookeville every 30,000 miles or when your owner’s manual recommends it. Our auto shop in Cookeville, TN, is the best in the city, and we’d be happy to make sure your transmission fluid is always bright red.


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