When was the last time you checked your transmission fluid? If you answered "never," don't worry – you’re like most drivers!

While most car owners know to maintain their motor oil, many are unaware that they should regularly check their transmission fluid and schedule transmission fluid maintenance per manufacturer recommendations.

But how do you check your transmission fluid? Examining the transmission fluid color can be an indication of the state of your transmission.

Keep reading to learn more about why transmission fluid matters and how to understand transmission fluid color.

What Is Transmission Fluid?

Transmission fluid is a viscous fluid formed from chemical reactions or crude oil and reshaped hydrocarbons, depending on whether the transmission is automatic or manual.

The fluid travels through a vehicle’s transmission to lubricate and protect the internal components from wear and tear. It also prevents overheating by cooling the transmission as it circulates.

Transmission fluid acts as a hydraulic fluid and assists in the torque converter, valve body and clutch friction operation.;

Transmission fluid’s primary purpose is to ensure vehicles can effortlessly shift into and engage a gear. It maintains the transmission's inner elements, allowing them to provide just the right amount of power for the driven speed.

The Importance of Healthy Transmission Fluid

Transmission fluid plays a crucial role in the operation of your vehicle. It essentially hydrates your transmission to ensure it can go the distance. When the transmission fluid is lacking or compromised, it exhausts your transmission, and your vehicle may display signs such as:

• Lack of power
• Overheating
• Noisy while in neutral
• Puddles beneath your parked car
• Burnt odor
• Slipping, or trouble shifting gears
• Grinding or shaking feeling while driving
• Roaring noises

When left unattended, low or compromised transmission fluid leads to extensive damage and costly repairs. Luckily, you can keep an eye on your transmission fluid by regularly checking its color. Let’s discuss how to evaluate transmission fluid color.

What Color Should Transmission Fluid Be?

Transmission fluid color is translucent but often dyed bright red so it’s easy to identify from other vehicle fluids. However, some transmission fluids may also be dyed blue or purple.

Over time, debris mixes with the fluid, and it naturally darkens. A dark red color is not an immediate cause for concern but should prompt you to keep an eye on it or schedule future maintenance.

So, how do you check transmission fluid color? Most vehicles contain a transmission fluid dipstick that reveals both the color and level.

However, the process for checking transmission fluid color can vary greatly by vehicle. Some newer vehicles don't have a transmission fluid dipstick. In this case, you may need the help of a professional.

Your owner’s manual or vehicle service manual should be able to point you in the right direction. Your manufacturer should also have specifications that tell you how often a transmission fluid change is needed, but if you’re unsure, consult a professional automotive mechanic.

What Each Color of Transmission Fluid Means (Color Guide Chart)

Now that we know what a healthy transmission fluid color looks like, let’s discuss what other transmission fluid colors mean.

                                                                          Image source: Auto Trends Magazine

Bright Red

As previously mentioned, bright red transmission fluid indicates it’s new or like-new. Your transmission should be in excellent shape, and you need not worry about getting the fluid changed.

Dark Red 

As you drive, debris particles mix with the fluid and darken it slightly. This is a natural occurrence and does not affect your vehicle’s performance.

Brown

If your transmission fluid color appears muddy or brown, it’s because it’s begun to oxidize. The elements of transmission fluid that keep your vehicle running successfully are compromised, and you should schedule a fluid transmission change or flush soon.

Dark Brown or Black

If your transmission fluid color is dark brown or nearly black, contact your automotive technician as soon as possible. Your transmission is receiving little to no lubrication and is on its way to becoming a costly repair. You may also notice your vehicle struggling to engage in gear or chattering as you drive.

Pink

Transmission fluid turns pink when diluted with water or engine coolant, usually due to a leak in the radiator. Pink transmission fluid requires immediate attention as coolant circling throughout your transmission can quickly damage it.

How to Fix Transmission Fluid Problems

If your transmission fluid appears brown or black, you’ll likely need a transmission fluid change or flush.

A transmission fluid change involves draining dirty transmission fluid and refilling it with fresh fluid.

If you’re planning on changing your transmission fluid on your own, check your vehicle's service manual to ensure you’re using the proper fluid. Adding the wrong product can damage your transmission. It also shouldn't go without saying that transmission fluid changes can leave up to 30% of the old fluid in your transmission and compromise the fresh product sooner than necessary.

For this reason, some car owners prefer a fluid flush. A flush uses specialized equipment to clear out and clean your transmission, torque converter and cooler lines before adding fresh fluid.

Contact a transmission provider or your vehicle manufacturer ifyou’re unsure which service is best for you or aren’t entirely sure you need one. They’ll be able to point you in the right direction.

Universal Technical Institute’s (UTI) transmission provider, AAMCO, provides various transmission flush services that they can help you choose from. 

AAMCO is an industry-leading total car care provider that provides  UTI’s automotive mechanic school with relevant training aids at select campuses, as well as networking and potential employment opportunities.¹

Transmission Fluid Color FAQ

What Color Is Transmission Fluid When It’s Leaking?

Transmission fluid color is typically dyed red, so it is easy to identify. The transmission fluid leak color will likely be red-brown hue and oily consistency.

The location of the puddle is another sure way to determine if the liquid is transmission fluid, as it typically leaks toward the front-middle of the vehicle.

What Color Is Bad Transmission Oil?

A bad transmission fluid color oil is muddy brown, dark brown or black. If you notice this, schedule transmission maintenance as soon as possible before damage occurs.

How Do I Know When My Transmission Fluid Needs Replacing?

Your vehicle's service manual should have instructions on how often to change your transmission fluid. The color of the transmission fluid can also determine if it needs replacing. You can use the transmission fluid color chart above as a guide.

Stay Informed at UTI

Are you interested in vehicle mechanics? Want to learn how to repair and maintain transmissions? Consider pursuing a career as a mechanic.

UTI’s automotive mechanic school, diesel mechanic school, and motorcycle mechanic school use a blend of online learning and hands-on training in the labs from expert instructors to provide students with a foundation of knowledge and technical skills.

From maintenance to diagnosis and repair, students are prepared for the industry upon graduation.

Volkswagen Technician and UTI graduate, Austin Adair, shared, “Coming out of UTI I was up to date right away. I knew how things worked and how they were evolving. I feel like I got a jump on everything.”⁶

Ready to get started? Request more information or contact an Admissions Representative today. 

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