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What Color is Transmission Fluid Supposed to Be?

The transmission is one of a vehicle’s most vital components. With almost 1000 finely engineered, precision parts, it is one of the most complex and expensive units to repair or replace. The automatic transmission combines electrical & mechanical systems, hydraulics and computer processors to smoothly shift through the gears and transfer engine power to the drive wheels.

The one component that is critical to all the parts in a transmission working properly together is the Automatic Transmission Fluid, or ATF. Every ATF is a precise blend of different chemicals in oil because it has to do a lot of different jobs. An ATF:

  • Acts as a hydraulic fluid, to engage clutch packs & shift the gears.
  • Acts as a gear and bearing lubricant but also provides and maintains correct frictional properties for smooth clutch engagement as well as efficient power transfer.
  • Acts as a corrosion inhibitor and wear protection for the Planetary Gear sets.
  • Has to flow easily from minus 40 degrees Celsius to over 200, even in fine valve assemblies.
  • Must have low conductivity, and be compatible with all electronic components.

Using the right ATF is critical to the performance and long life of your transmission and that’s why maintaining it is so important. The color of a transmission fluid can also provide a quick and easy insight to the health of your transmission.

Red. Clean transmission fluid is a dark red, translucent color. Transmission fluid is actually dyed for identification purposes. Over time, the fluid will become darker, causing it to go from its original red to a dark, burnt color due to age and vehicle use. It can also occur when contaminants flow through an improperly functioning transmission filter. Below is a color chart portraying the typical stages your transmission may go through:

This answer varies on your car’s year, make, and model. You should always consult your owner’s manual for the manufacturer’s ATF specifications recommended for your vehicle. As automatic transmissions become more complex, there’s a need for more technologically advanced fluids to ensure vehicle reliability. Getting the right oil for your car is key to ensuring your transmission operates as designed and you get a smooth driving experience every day.

Castrol®, with over 100 years of experience in developing transmission fluids, and being the choice of many leading car and transmissions manufacturers for factory-fill products, offers a range of automatic transmission fluids for your car’s requirements. Providing you the peace of mind that you are selecting the right oil for your vehicle.

Castrol® Transmax® with Smooth Drive Technology™ automatically adjusts its friction level in response to changing pressures on critical transmission parts – delivering enhanced protection and a smoother drive for longer, eliminating noise and shutter keeping things running like clockwork.


If you have a feeling it’s time for a change, make an appointment today at a Pep Boys near you