An automatic transmission, or transaxle, uses hydraulic pressure to change gears up and down. The transmission uses transmission fluid and a pump to make the pressure and move the parts.
Since about 2007, some car makers have stopped installing a means to check the level of fluid in the transmission. Those transmissions are sealed, and some do not have a filter. Instead, they rely on a sensor to tell you when the fluid is low, and require a complete fluid change at regular intervals.
If your car does have dipstick tube and a means to check the fluid, here’s how you do it.
CHECKING THE FLUID LEVEL
1. LOCATE THE TRANSMISSION DIPSTICK.
On this front-wheel-drive car it is well-marked and easy to access. It may be harder to find on a rearwheel- drive car. Check your owner’s manual for the location
2. TURN ON THE VEHICLE AND ALLOW IT TO RUN.
This allows the pumps to push the fluid into all the passages in the transmission. Be careful to not get near any rotating parts on the engine.
3. CLEAN THE DIPSTICK.
With the car running, pull the dipstick, wipe it off, and reinsert it. This will give you a fresh reading while the transmission is at normal operating levels.
4. PULL THE DIPSTICK AND CHECK THE LEVEL.
This dipstick has readings for when the transmission is cold or if it is hot. The fluid in the transmission will expand when warmed up, so check your owner’s manual and see if it needs to be checked when warm. Examine the condition of the transmission fluid. If it is black with burnt material or soot, or if it looks milky or hazy, you might need to have it changed or have the transmission serviced.
If the level is okay, replace the dipstick and turn off the car.
If your transmission fluid is low, you can add more. Take care not to overfill the transmission, and be sure to use the fluid recommended by the manufacturer.
1. DETERMINE WHAT TYPE OF FLUID YOU NEED.
Some manufacturers print the type of fluid you should use on the dipstick or tube. This will also be in the owner’s manual.
2. FILL THE TRANSMISSION.
With the engine turned off, insert a funnel in the dipstick tube and pour in the fluid. A long funnel is good for tubes at the back of the engine that are hard to get to. Go slow. It’s better to add a little, recheck, and then add more than to put in too much.
3. RECHECK THE LEVEL
Let the fluid run down the tube for a couple of minutes, and then recheck the level of the transmission. Continue until you have filled the transmission to the required level.