Do you need to grease your 2003 ford ranger or is it factory sealed?

No, your 2003 Ford Ranger's differentials and other drivetrain components are not factory sealed. They require periodic lubrication (greasing). The frequency depends on driving conditions (off-road vs. highway), but a general recommendation is every 3,000-6,000 miles or at least once a year.

Check your owner's manual for the specific recommendations from Ford. It will indicate the recommended grease type and the zerk fittings (grease nipples) that need to be greased. If you can't find your manual, you can likely find a PDF version online by searching for "2003 Ford Ranger owner's manual."

Ignoring this maintenance can lead to premature wear and failure of your drivetrain components.