Ford's official recommendation was often a somewhat vague "as needed" or based on severe service conditions. However, a general guideline used to be around every 100,000 miles for normal driving conditions. For severe service (heavy towing, frequent stop-and-go traffic, extreme temperatures), changes would be recommended much sooner – potentially as frequently as every 30,000-50,000 miles.
Instead of relying on a mileage-only schedule, it's much better to:
* Check your owner's manual: This is the most important source of information. While it might not give a specific mileage, it will outline factors to consider and might suggest a schedule based on your specific usage.
* Have the fluid inspected by a professional: A mechanic can check the fluid's color, smell, and condition. Dark, burnt-smelling fluid is a strong indicator that a change is overdue. They can also assess the condition of the transmission itself.
* Consider a flush or drain and fill: A complete flush is more thorough but can sometimes introduce problems if debris gets dislodged. A drain and fill replaces a portion of the fluid. This is often a less disruptive, safer option for older vehicles.
In short: Don't solely rely on a mileage number for a 2005 F-150. Regular professional inspection is crucial. Ignoring transmission fluid maintenance can lead to costly transmission repairs or failure.
