Transmission Fluid is checked through a dipstick much like the oil. If you can check it yourself, be sure your vehicle is on level ground.
Unlike the oil, transmission fluid is checked when the engine is hot (has been running for 5 minutes or more). Never overfill the transmission fluid.
If you discover that the fluid is low, get your transmission checked and the fluid level brought to normal.
Because of the technical nature of the transmission, we recommend that you let a mechanic add or change your transmission fluid.
Adding the wrong kind of transmission fluid can damage your car.
Also, certain makes and model vehicles have a sealed transmission unit or one accessible only by a mechanic. See a trained mechanic and have your fluid levels checked.