Transmission fluid lubricates the transmission components to keep the transmission working and from having its internal parts contacting and damaging one another. This post explains how to check for bad transmission fluid, how to check the fluid level, and what to do if it needs to be changed.
How to Check the Transmission Fluid’s Condition
Bad fluid will look brown and dirty.
If what is drained from the transmission looks brown and dirty, the fluid is contaminated and overheating, which means it’s time to flush and replace the fluid.
Clean fluid will look red and clear.
The fluid may also be in between those two colors, but the fluid should be more red and clear than it is dirty and dark.
How to Check the Transmission Fluid Level
Steps for Checking the Transmission Fluid Level
- Warm the Engine Up to Running Temperature
Drive the vehicle and warm the engine up to running temperature. The vehicle will need to be at running temperature to accurately check the transmission’s fluid level and condition.
- Park the Vehicle on Level Ground
Park your car or truck on solid, level ground, like asphalt or concrete.
- With the Engine Running, Remove the Transmission Oil Dipstick
With the vehicle running, find the transmission dipstick under the hood. It usually has a red handle. Some vehicles may have a red or black cap and fill plug.
- Clean the Transmission Oil Dipstick and Reinsert It
Clean any fluid from the transmission oil dipstick with a cloth or paper towel and fully reinsert it into the dipstick tube.
- Check That the Fluid Level Is Between the Two Marks
Remove the dipstick. Confirm the fluid measures between the upper and lower markings on the transmission oil dipstick. It is better if the fluid is near the upper marking. If the fluid is below the markings, the fluid level is low.
Check Your Vehicle’s Transmission Fluid or Replace It Yourself
There may be a different process for checking the fluid level on some vehicles, like in the video below. Find out how to check and service your own transmission with a video specific to your year, make, and model from 1A Auto’s how-to video library.
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