Your car's automatic transmission system is one of several hydraulic systems in your car. To maintain your system, you must check the transmission fluid periodically to make sure there is enough fluid of sufficient quality available for your transmission to perform correctly. Keep reading for detailed instructions on how to check and add fluid to your automatic transmission system.
1Park your car on a level surface with the engine running. You may want to shift the transmission briefly through each of its gear settings before putting it in park.Ad
2Raise the hood. There's usually a lever on the inside of your car that pops the hood, usually near the left hand side of the cockpit. Consult your owner's manual if you are unable to find it.
3Find the automatic transmission fluid pipe. On many newer cars, the transmission fluid pipe will be labeled; if not, consult your owner's manual for its location.
- On a rear-wheel drive vehicle, the dipstick is usually in the rear of the engine, above the oil reservoir.
- On a vehicle with front-wheel drive, the dipstick is usually in the front of the engine and is connected to the transaxle. On most cars, this will be to the right of the oil reservoir.
4Pull out the transmission fluid dipstick. Wipe the dipstick on a clean rag or paper towel, reinsert it and pull it out again to check the transmission fluid level. The fluid level should be between two marks labeled either "Full" and "Add" or "Hot" and "Cold."
- Usually, you should not have to add transmission fluid. If the level is down significantly below the "Add" or "Cold" line, you probably have a system leak and should take the car to your mechanic.
5Check the condition of the transmission fluid. Good automatic transmission fluid is usually red (although sometimes pink or light brown), without bubbles or odor. If any of the following conditions are true, take your car in for servicing.
- If the transmission fluid is a discolored brown or smells like burnt toast, the fluid has boiled itself into uselessness and can no longer dissipate the heat the transmission generates. The fluid can be tested further by putting some on a clean paper towel and waiting 30 seconds to see if it spreads. If it does not, the fluid must be changed immediately, or the transmission itself will suffer serious damage.
- If the transmission fluid looks milky brown, it has been contaminated by coolant from the radiator through a leak in the automatic transmission fluid cooler. Take the car to your mechanic at once.
- If the transmission fluid is either foamy or bubbly, there is too much fluid in the cylinder, the wrong transmission fluid has been used or the engine has a plugged transmission vent.
6Add transmission fluid, if necessary. Add the fluid a little at a time, rechecking the level periodically, until it is at the correct level.
- For your first run, you will probably need to add between three and four quarts of transmission oil if you've gutted the car completely and are starting from scratch. Otherwise, check the dipstick regularly to avoid overfilling the fluid pan.
7Run the car and take it through each gear if possible. This process allows the newly added transmission fuel to circulate and properly coat each gear, lubricating it. Start with the engine running and the car in park, if possible with the wheels off the ground. Go through First all the way to Third, including Drive, Overdrive, and Reverse gears, spending a minute or so in each gear to ensure proper coating. When finished, let the engine run for a couple minutes before putting it in Park.
8Check the dipstick again to determine how much additional fluid you may need to add, if any. Inspect the dipstick, as transmission fluid may have flushed from the pan to the gears, necessitating another fluid injection.
9Add the necessary amount of fluid to bring it to its proper level. Depending on whether you're just giving your transmission fluid a top-up or you're replacing the entire pan with new transmission fluid, you may need to add extra fluid at this point.
- If you're simply topping up, you may need to only add only a quart of fluid, or even less.
- If you've gutted the pan and are starting from scratch, you may need to add anywhere from four to 12 quarts, depending on the make and model.
10Finished. Your car's transmission fluid is now properly set and your car should be humming along.Ad