* 4x4 with manual shift-on-the-fly: This system uses a lever or switch (usually on the floor console or dashboard) to engage 4-wheel drive. The exact location and operation vary slightly depending on the specific trim level and options. You'll shift it into 4-High for off-road or slippery conditions. You MUST be moving at low speeds (under 20 mph or so) when engaging 4-High. Engaging it at higher speeds can damage the drivetrain. There's typically no 4-Low option on these systems; it would be a part-time 4WD.
* 4x4 with automatic shift: Some higher-end or off-road packages might have had an automatic 4x4 system, where a computer engages 4-wheel drive as needed. You generally wouldn't manually shift into 4WD in this case.
To find out how to shift your specific F-150 into 4-wheel drive:
1. Consult your owner's manual: This is the definitive guide for your truck. It will clearly show you where the 4x4 shifter is located (if it's a manual system) and how to use it.
2. Look for the shifter: If you can't find the owner's manual, look for a floor-mounted lever or a dashboard-mounted switch typically labeled "4x4," "4H," or similar. It may have additional markings for "2H" (2-wheel drive high) and potentially "4L" (4-wheel drive low range), but "4L" was less common in these models.
3. Be careful: Never attempt to engage 4-wheel drive at high speeds. Always do so at low speed on a level surface. Improper use can damage the drivetrain.
Without knowing the exact trim level and options of your 1998-2003 F-150, it's impossible to give more specific instructions. Referencing your owner's manual is crucial.
