To determine the correct amount, you need to consult your owner's manual. It will specify the correct fluid type and the amount needed for a fill or a complete fluid change.
If you don't have the owner's manual, you can usually find a PDF version online by searching "[year] [make] [model] owner's manual" on a search engine like Google.
Important Considerations:
* Fluid type: Using the incorrect type of transmission fluid can severely damage your transmission. The owner's manual will specify the correct type (e.g., ATF+4, Dexron III, etc.).
* Check the fluid level correctly: The owner's manual will describe the proper procedure for checking the transmission fluid level, which usually involves running the engine to operating temperature and then checking the level with the dipstick.
* Consider a professional: If you're unsure about any aspect of checking or adding transmission fluid, it's best to take your car to a qualified mechanic. Improperly servicing your transmission can lead to expensive repairs.