Here's a general outline, but this is not a substitute for consulting your owner's manual:
1. Identify your transmission: This is crucial. Look for a sticker on the transmission itself, or check your owner's manual. The manual will specify the correct type and amount of fluid.
2. Locate the fill plug: This is often on the side or top of the transmission. Again, your owner's manual will show you the exact location. It's usually a different plug than the drain plug.
3. Warm up the transmission: Run the engine for a few minutes to warm the transmission fluid. This helps ensure accurate measurement.
4. Gather supplies: You'll need the correct type and quantity of transmission fluid (as specified in your owner's manual), a funnel, rags, and possibly a pump if the fill plug isn't easily accessible.
5. Check the fluid level (if applicable): Some transmissions have a dipstick. If yours does, check the level *before* adding any fluid.
6. Add fluid: Carefully add the transmission fluid using a funnel. Do not overfill. Overfilling can be just as damaging as underfilling.
7. Check the level again (if applicable): If there's a dipstick, check the level after adding fluid to ensure it's within the correct range.
8. Replace the fill plug: Tighten it securely.
WARNING: This is a simplified explanation. Incorrectly servicing your transmission can lead to costly repairs. If you are not comfortable performing this task yourself, take your F-350 to a qualified mechanic. They have the correct tools, knowledge, and resources to properly service your vehicle. Improperly filling the transmission can cause serious and expensive damage. Your owner's manual is the single best source of information for your specific truck.
