When should you check your transmission fluid

If you're going to be checking the transmission fluid level at home, it's a good idea to warm up the car before you do so. If the car is checked while the engine is cold, it might give an inaccurate reading when you use the dipstick. After driving for about 10 minutes, park on an even surface and leave it running.

Step 1: Leave the engine running and open the hood to your car. The car must be warm when you check transmission fluid. Step 2: If you have an inline engine, look behind your oil dipstick, toward your windshield, to locate the transmission fluid dipstick.

Check the Level With the engine warmed up, leave the car idling in park on a level surface. Pull out the dipstick, wipe it clean, replace it slowly, and then pull it back out. Check the fluid level—how high the fluid comes up on the dipstick—against the "full" and "low" or "fill" marks on the dipstick.

Observe markings at end of dipstick. Your dipstick might have two markings for "full"—one warm, one cold. If the automatic transmission fluid level does not come up to the "warm" line, you'll need to add automatic transmission fluid.