As you know, a big part of keeping your vehicle running correctly is regularly changing its fluid. Because the fluid in your vehicle is needed to keep things lubricated and clean, things like dirt and metal shavings can be accumulated over time inside of the fluid. Hopefully, this debris will settle on the bottom of the pan, and not circulate through the system, and to help ensure your transmission remains clean, it's a good idea to change your transmission fluid.
While every vehicle is different, it is recommended to change the transmission fluid in your vehicle ever 30,000 miles, or every 30 months. You should always check your owner's manual to see the recommended times for your vehicle however. If you check the dipstick that goes into your transmission fluid and notice dark, or burnt-smelling fluid, you'll probably need to change your fluid sooner rather than later.
You'll first need to gather an automatic transmission filter kit, and some basic shop tools in order to get the job done. First, let your vehicle idle for a couple minutes and lay down some newspaper or cardboard underneath a 2-gallon catch pan. Turn your ignition off and remove the bolts from one side of the transmission pan. Next, slowly loosen the bolts from the other side to allow the pan to tilt and drain. Once all the bolts are off, you can pour the fluid left in the transmission pan into the catch pan. Then you'll want to clean off gasket surfaces on the pan and on the transmission housing.
Next, remove the old transmission filter, which contains fluid, and O-ring. After the old one is off, install the new transmission filter and make sure the O-ring seats in the appropriate outlet. Attach the new gasket to the pan with oil-soluble grease and torque the pan bolts to spec in a spiral pattern starting in the center. Then you'll want to fill your vehicle up with the appropriate amount of transmission, and start it up in order to check for leaks. If there are no leaks, congratulations! You've successfully changed your transmission fluid.