Before you lift your car, you should inspect your transmission to diagnose its health. Your car will need to be running to do this, so start the engine and let it run until it gets warm. With the gearshift in park and the emergency brake on, check the transmission fluid level using the dipstick located at the rear of the engine. It will be sticking out of the transmission or, if you have front-wheel drive, out of the transaxle.
Now, pull out the dipstick, wipe it on a clean rag and reinsert it into the tube, making sure it's seated completely. Pull the dipstick out again and look at the film of fluid on the end. Some dipsticks indicate add levels, and some show full levels for cool, warm or hot fluid. If your transmission is in good health, the automatic transmission fluid (ATF) should not be low. It should also have a pinkish to reddish color and smell like petroleum.
If the fluid level is low and you're in between service, add transmission fluid and keep checking every two weeks. If your transmission fluid is consistently low or appears burned and dirty, you could have a more serious transmission problem. Take your car to a mechanic so the transmission can be thoroughly inspected.
If the fluid level and quality looks good and it's been 20,000 miles (32,187 kilometers) since your last transmission service, you should proceed with the fluid change. To do this, you'll need to raise your car. You can use jack stands, but ramps make the job easier. Ramps offer good stability and lift your car 7 to 9 inches (18 to 23 centimeters) off the ground. If you opt for jack stands and do the work on a gravel driveway, consider placing a piece of plywood under the stands to prevent them from digging into the ground. Either way -- jack stands or ramp -- have wheel chocks ready to keep the rear tires from rolling.
Fluid changes should only be done when the engine and transmission are at normal operating temperatures. With your vehicle raised, let the engine idle for a few minutes, then turn it off. When the transmission fluid is still warm, but the vehicle has cooled down, you're ready to remove the old transmission fluid. Keep reading to learn how.