San Diego Auto Repair

Checking your car's transmission fluid level

It's no exaggeration to say that automatic transmissions run on oil, more properly called automatic transmission fluid, or ATF.

Unfortunately, in recent years, many manufacturers have started to eliminate the transmission fluid dipstick. Called sealed units, these transmissions require a much more involved process to check fluid levels than in days gone by. The process often involves electronic testing devices, such as a computer scan tool. This puts checking the transmission fluid level beyond the capabilities of the average car owner.

If your car doesn't have a dipstick, you should have your local repair shop or dealership check the transmission fluid level at least a couple times a year, even if you don't notice a problem with the transmission operation. A good time to do this is while you're having the engine oil changed, in the spring and fall.

But if your car does have a transmission dipstick, you should check the transmission fluid level at least once or twice between oil changes. Your car's owners manual should provide a detailed procedure for checking the transmission fluid level in your car.

If you don't have an owner's manual, here's a basic procedure that'll work on just about any car with a transmission dipstick.

WARNING: Checking the transmission fluid level requires working under the hood of your car with the engine running. This can be very dangerous if you aren't sure what you're doing. Watch out for moving components, such as fans, fan belts, pulleys, etc. If you aren't comfortable with this procedure, always take your car to your local service station to have the transmission fluid checked.

1. Make sure your car is on level ground.
2. Start the engine.
3. Bring the engine and transmission to normal operating temperature. The easiest way to do this is to check the fluid level right after driving the car for a while.
4. Hold your foot on the brake, and work the shifter slowly through the gears. Give the transmission a second or two in each gear range.
5. Put the shifter all the way back into park.
6. Set the parking brake.
7. Carefully open the hood.
8. Find the transmission dipstick (your owners manual should show you where to look for the transmission dipstick):
   Rear wheel drive vehicles - the dipstick will usually be on the passenger's side of the engine compartment, near the back of the engine.
   Front wheel drive vehicles - the dipstick will usually be on the driver's side of the vehicle, on either side of the transmission
9. Remove the dipstick, and wipe it off with a clean rag or paper towel.
10. Slide the dipstick all the way back down into the transmission fill tube.
11. Pull the dipstick back out, and check the fluid level against the markings on the end of the dipstick.
12. Add fluid as necessary.

Always use the fluid recommended by the manufacturer. See the consumer information on fluid types to be sure you're using the right fluid for your car. If the transmission requires more than a quart, or is using fluid regularly, take your car in to have it checked for leaks.

And if you're unsure of the procedure or where to find the transmission dipstick, check with your local ATRA member center: They'll be happy to show you where the dipstick is, and how to check the fluid level.