To find the correct amount, you must consult your owner's manual. The manual will specify the exact capacity for your truck's transmission. Alternatively, you can:
* Check the transmission dipstick: If your truck has a dipstick (many do), this is the easiest way to find out how much fluid is needed. Check the fluid level when the engine is running and at operating temperature. However, this only tells you the current level, not the full capacity for a complete change.
* Look up your truck's VIN: Using your Vehicle Identification Number (VIN), you can often find the exact transmission type online through a parts website like AutoZone, Advance Auto Parts, or Napa Auto Parts. Then search for the transmission fluid capacity for that specific model.
Attempting to add ATF without knowing the correct amount can be harmful to your transmission. Too much fluid can cause damage, as can too little. Always refer to your owner's manual or consult a qualified mechanic for accurate information.