Transmission fluid guide: What color is it supposed to be?

Updated Mar 09, 2021 | Same topic: Handy Maintenance Tips

The color tells you when to change it.

1. Functions of transmission fluid

There are various components that are rotating and cranking within a single second of driving. For example, an idling car records around 600 to 1,000 revolutions per minute (RPM). This number increases significantly as you drive especially when cruising down highways.

By the sound of it, the components of your car take a lot of pressure and stress to operate properly. This is where transmission fluids join the fray. Transmission fluids lubricate the gears within the transmission gearbox so these components won’t wear out fast resulting in a longer lifespan.

Removed gears

Gears help transfer the mechanical energy from the engine to the wheels

On average, you must replace your car’s transmission fluid every 55,000 km to 90,000 km. The mileage intervals can vary depending on how frequently you use your car and on which road conditions your car drives on a daily basis. The harsher the driving condition, the faster you will need to replace it.

Transmission fluids also help cool down and clean the rotating components such as the gears. The more the gears are cooled, the more efficient the components work. With all that being said, transmission fluids are essential in keeping your engine running in ideal condition.

A woman inside a car

Bad transmission fluids can produce a burned smell

If you decide to not replace your transmission fluid in time, then you can expect a lot of faults in your car’s transmission system. The dirty transmission fluid will not cool down your transmission as effectively as a new one. Since it functions as a lubricant, you can expect your gears to wear faster as well.

2. What color is transmission fluid supposed to be?

Transmission fluids are purposely dyed red for few reasons. The main reason why car parts manufacturers use red is to determine the condition of the transmission fluids better. The more the shade of red is clearer, the newer its condition.

Red and black transmission fluids

Difference between good and bad transmission fluids

Over time, transmission fluids will change color due to various causes during an engine operation. Since transmission gears work at a high temperature, the color of transmission fluids tends to go from red to a darker or burnt color which is something we would like to avoid.

Aside from high temperatures, the color of the transmission also changes due to debris. Transmission fluids accumulate debris from various components such as worn gears and bushings. As such, debris in transmission fluids is pretty much inevitable as you drive your car.

An automatic transmission

Take care of your transmission to avoid wearing them fast

If you happen to notice that the color of your transmission fluid is changing from red to a darker color, then it could be a good indication that you need to change your transmission fluids. Checking the condition of your transmission is easy and you don’t need special tools to do so.

The first you might want to do is to locate the transmission fluid dipstick in your engine bay. It is usually located behind the engine colored red. The yellow dipstick is for the checking of oil so you might want to check as well since you are already in the same area.

Checking transmission fluid

Inspect the color of your transmission fluid properly to get a correct reading

Once you found the transmission fluid dipstick, start your engine first so you can get an accurate reading. You start your engine first because the level of a transmission fluid varies depending on the operating temperature of the engine. Pull out the red transmission fluid dipstick and wipe it off first with any rug.

Put it back all the way down and pull it out again then assess the transmission. If it is showing more red, then it is still close to new. If it is showing a dark color, then you might want to change it.

>>> Related: Can you use transmission fluid for your power steering?

3. Diagnose transmission fluid problems with this color chart

Red

As standard, transmission fluids are dyed red for identification purposes. If the color of red is still strong, then it could mean that it is still new. As such, you are not required to replace your transmission fluid at this color. Be sure to record the time you decided to change your transmission fluid so you can have an idea when to replace it after few years.

Light Brown

With light brown color, it means that your transmission fluids can still run for a long time. Some people even claim that transmission fluids at this point work better than a new one. The dirty transmission fluid provides a grit in the substance resulting in better friction. Regardless, you still don’t have to worry about your transmission fluid if it shows a light brown color.

Dark Brown

Transmission fluids with a dark brown color pretty much tell you they should be replaced. At this point, dark brown transmission fluids will not provide adequate lubrication and transmission cooling which all results in inefficiency. However, do note when was the last time you change your transmission fluid. Tell your mechanic the replacement date so he/she can access whether your current transmission fluid can still run for few kilometers.

Black

Once your transmission fluids turn black, then it is done. Driving with a black transmission fluid can cause high-temperature operation within the gears which leads to wearing these components. Gears will also cause heat when in contact with each other as they don’t have enough lubrication for an ideal operation.

 Transmission fluid color What it means  Recommended action 
 Red  New or like new condition  No action needed
 Light brown  Good condition  No action needed
 Dark brown  Old and dirty  Fluid change
 Black  Old, dirty, and/or oxidized  Fluid change

>>> Related: Dispose of your car fluids properly

4. Transmission fluid: FAQs

Q: Why is transmission fluid red?

Transmission fluids are dyed red by manufacturers for identification purposes.

Q: How long do transmission fluids last?

Transmission fluids last for around 55,000 km to 90,000 km, depending on how frequently you drive your car.

Q: How can I check my transmission fluid?

Find the red dipstick usually located behind your engine.

Q: How much is transmission fluid in the Philippines?

The price can vary depending on the type and the volume. But you can get one for around Php 300 for one liter.

Q: Is a black transmission fluid bad for my car?

Yes, black transmission fluid is a strong indication that you need to replace it as soon as possible.

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Rex Sanchez

Rex Sanchez

Author

Rex started off his career in the aviation industry before entering Philkotse as a staff writer. Two things excite him the most: first is staying up to speed with the latest news in the industry that uses engines as their heart and soul. The second is imparting them in a well-detailed manner. His passion for anything with wheels started when he was young – from Tamiyas to family-friendly sedans, and anything in between.

Someday, Rex only wishes to drive on random highways with friends in a third-gen Mitsubishi Delica with aftermarket sunroofs, if he couldn’t get the Starwagon Super Exceed edition.

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