The manual will specify the type of fluid (e.g., ATF+4, Dexron III, etc.) and may also include the recommended fluid's viscosity. Using the incorrect fluid can severely damage your transmission.
If you don't have the owner's manual, you can try:
* Looking for a sticker under the hood: Sometimes there's a sticker with fluid specifications.
* Searching online: Use the vehicle's VIN (Vehicle Identification Number) and search for a digital copy of the owner's manual. Many manufacturers make these available on their websites.
* Consulting a parts store: Provide them with the year, make, model, and engine size of your truck. They can look up the correct fluid based on that information, but double-checking with your manual is always safest.
Don't guess! Using the wrong fluid is expensive to fix.
