Here's why:
* Safety: Adding ATF with the engine running can create a dangerous situation. The fluid is hot and under pressure, and adding it while the engine is running could cause it to splash and burn, leading to serious injuries.
* Overfilling: Adding ATF with the engine running makes it difficult to accurately check the fluid level. You could easily overfill the transmission, which can lead to damage and costly repairs.
* Air Contamination: Adding ATF while the engine is running can introduce air into the system, which can cause problems with the transmission's performance.
Here's the correct procedure:
1. Park the car on a level surface.
2. Turn the engine off and let it cool down for at least 15 minutes.
3. Locate the dipstick for the transmission.
4. Remove the dipstick and wipe it clean.
5. Reinsert the dipstick fully and remove it again.
6. Check the fluid level on the dipstick. It should be within the "hot" range.
7. If the fluid level is low, add ATF slowly, checking the dipstick frequently.
8. Replace the dipstick and make sure the transmission fluid cap is securely closed.
Always refer to your owner's manual for specific instructions and safety precautions.
Important Note: If you are unsure about adding ATF or have any concerns about your transmission, consult a qualified mechanic.
