All ION models except years 2004 and earlier require planned changes of their transaxle fluid at specific times-wait until the fluid cools down fully before changing it. Buy the right fluid and a fresh filter before you start work on your car. You will need four items for this job: wheel supports (jackstands), a trash collector pan, plain newspaper, and clean towels. Take the car to the height your car permits, remove the front and side pan bolts, half-release the rear pan bolts, and carefully rock the pan to let the fluid flow out. Wiggle out and take off the last bolts, pan, and the gasket material, and clean off the surface where the gasket connects to the gearbox. Remove the transaxle pan, clean out all its contents, and keep track of a small magnet that's often found there. Pull out the existing filter, then take off the old seal with a prying tool. Put new filter seal and filter in place. Clean the surface of the seal on the transaxle pan, put the new seal on, and tighten the pan bolts a little at a time. Put the car onto the ground and pour the right amount of automatic transmission fluid in through the cap where you pour and check the fluid level. There's no need to routinely check your automatic transmission fluid unless you drain and refill it, or observe a leak. Not having enough fluid makes your car slip gears, while there's too much fluid can make it foam. Get the car running and put the shift lever through all gears from neutral, ending with Park. You need to let the fluid cool down before checking if you drove the car under specific conditions. Turn the engine on and check the fluid level by taking off the vent or filling cap while the engine runs. To check the fluid level, make sure the end of it is visibly at the bottom of the check hole, and add fluid until it drops there. Check the oil, and if it looks brown with a burning smell, you need to replace it. Use a wrench to firmly bolt in the check plug after, and look for any fluid leaking under the car during the first few drives. Throw out used engine oil in an approved way, avoiding both dumping on the earth or rinsing it into drains.