What Color Should My Vehicle’s Transmission Fluid Be?

Before we get into the color of your vehicle’s transmission fluid, let’s talk about what it does so you understand why it is so important. Transmission fluid acts like motor oil in the transmission. It lubricates the moving parts, cleans them, and keeps them cool. Transmission fluid also acts as a hydraulic fluid to help the transmission shift gears. John’s Auto Care advises that you should have your transmission fluid changed every 30,000 miles on average. This ensures that you always have fresh and functional transmission fluid in the transmission.

Bright Red

New transmission fluid is bright red. The red color is a translucent color. This fluid is viscous and does an excellent job of protecting the transmission. Bright red transmission fluid does not need to be changed. It is capable of lubricating, keeping the transmission clean, reducing heat production, and helping the transmission shift gears.

Light Brown

As the transmission fluid ages, it tends to turn light brown or orange. Usually, this fluid is still okay. It remains viscous, translucent, and able to do its job. This being said, once the transmission fluid begins to darken, it’s time to think about getting the transmission fluid changed. You may not have to do it just yet, but you will in the near future.

Dark Brown

Dark brown transmission fluid means the fluid is beginning to oxidize. Oxidation occurs when air bubbles begin to develop in the transmission fluid. Oxidized transmission fluid is not effective. It cannot lubricate or clean the moving parts, nor can it reduce the heat that they generate. You may also notice that your transmission is having problems shifting gears. Dark brown transmission fluid needs to be changed right away.


If you ignore the fact that your transmission fluid needs to be changed when it is dark brown, it will eventually turn black and begin to damage your transmission. Black transmission fluid is opaque and fully oxidized. In other words, it can no longer do its job at all. In fact, you may begin to have severe transmission problems such as a refusal to shift gears or go into gear.


As an aside, if your transmission fluid is pink, you have a breach between the cooling system and your vehicle’s transmission. Pink transmission fluid that is frothy is transmission fluid with engine coolant in it. This diluted solution will seriously damage your transmission.

John’s Auto Care in Roseville, CA, would be happy to check your transmission fluid to see if it needs to be changed and to make sure that the levels aren’t low. Give us a call today to schedule an appointment.

Photo by chat9780 from Getty Images via Canva Pro

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