What’s in a color? The answer is a ton of information when it comes to transmission fluid color. It is one of the best ways to tell the overall health of your transmission.
What does healthy transmission fluid look like? The short answer is a nice amber color. And, that is assuming that you even have a manufacturer that starts with amber transmission fluid. There are some vehicles that use other colors, but for the most part they all use a transmission fluid that starts with some sort of bright red clear color.
All bets are off once the transmission fluid leaves the bottle. As soon as it enters the case it gets to work doing many jobs that are required of it. The fluid will begin to darken in color right away. This changing of the color doesn’t necessarily mean that there’s anything wrong.
There is simply an amazing amount that you can learn about a vehicle by looking at the transmission fluid. Just like motor oil, automatic transmission fluid gets darker with age. This is itself does not necessarily indicate a problem. Heat can cause ATF to darken over time.
Light Amber or Red Colored Fluid
The red color that you see in transmission fluid is from a dye added to it. Without it there would be almost no color to the fluid at all! Don’t be deceived if your fluid looks great. The color of the fluid is not an indication of transmission wear, or the last time that it was serviced.
If yo check your transmission fluid and it appears as a nice maroon color, that is an indication of fluid that has been in the case for quite a few miles. Heat causes the dye in the fluid to change color and get darker. Fluid that is this color is usually just fine. In fact, some ATF even comes that dark straight out of the bottle.
If you are having difficulty distinguishing from the color of your transmission fluid and motor oil, than you officially have dirty transmission fluid. Dirty does not mean dangerous though, and is not cause for alarm by itself. If the only thing that appears to be wrong is that the transmission itself is in need of a proper a servicing.
You’ll see the situation a lot where someone is looking to but a car and they are really put off by the dirty fluid. It is not an indication that anything is wrong with the car. But, brown fluid should serve as a warning that the maintenance schedule has not been followed.
Extremely Light Pink Fluid
This color is an indication that antifreeze or water has corrupted the transmission. Of all of the colors mentioned, this is the one that would give me the most concern. Water is almost impossible to get out of the transmission. It usually gets in there through a failing radiator. It can also get in there if you drive through floodwater.
If you have fluid that is this color get your transmission looked at as soon as you possibly can. Water is actively destroying your transmission. Anti-Freeze is especially corrosive.
Water contaminated transmission fluid can also have a foamy look to it. This will occur when the radiator or damaged line is allowing bother air and water in.
Black Transmission Fluid
While amber, brown, and black are usually harmless, that is not the case with black transmission fluid. The reason that the fluid has gotten to be black is because of issues in the transmission.
To the untrained eye, brown and black transmission fluid have similar colors. If you are unsure give it a sniff. Black transmission fluid smells. It smells bad because something has burned in order to get that smell. It is usually caused by worn and slipping clutches, torque converter problems, or other transmission failure. It is an indication of a serious problem and the transmission is going to require servicing.
Silver Tint or Silver Shavings
If you run into any of the colors above and find silver shavings in it, you have a major problem with the transmission. I know most mechanically inclined people are thinking “well of course there’s a problem”, but you never know who is going to be looking to a page like this for help.
This indicates metal on metal friction. Parts are actively grinding against each other. Failure is imminent. Get your transmission serviced as soon as possible.
What happens is you overfill the transmission fluid?
The transmission fluid may foam and ironically become starved for lubricant. More on that here: http://www.doityourself.com/stry/can-too-much-transmission-fluid-hurt-a-vehicle
What does Automatic Transmission Fluid do?
ATF moves the heat generated by the engine to the radiator. It lubricates the transmission, and it moves the power through the torque converter. That’s a lot for one fluid to do.
Transmission fluid is a type of hydraulic oil. It is highly flammable. A motor uses oil for lubrication, water for cooling, and a crank and pistons to transfer energy to the rest of the vehicle. Transmission fluid combines all three of these jobs into one fluid. It needs changing way less often and is often one of the most neglected parts of the vehicle.
Looking at the coloration of the transmission fluid is a great way to determine what is going on inside your transmission.. Remember, a color other than red or amber does not necessarily indicate a problem. Regardless of the color of the fluid, if the it gives off an odor and smells burnt, get the transmission looked at.