hi im new here been a ford man all my life but my first question i could use some help with i own a 2002 ford f150 fx4 with a 4.6 in it my question does it have a limited slip diff in it?

 

yes fx4 comes with a 3.55 ls

i have the exact same thing

 

Look at the axle code on the door sticker. If it is a letter and a number, it is limited slip. If 2 numbers, it is an open diff. Having the FX4 does not guarantee you have a LS.

 

The FX4 package should have limited-slip as standard, but it's possible that the truck was ordered with open gears too. I've seen both 3.55 and 3.73 geared FX4s

As kingfish posted, check the axle code on your door jamb. there's a sticky somewhere on the forum here that has a breakdown of what each code means as far as gear ratio and diff type.

 

here's a link to the info http://www.drivetrain.com/Fordtrkratio_posidata.html

 

That list is missing one code for whatever reason. B6 is a 3.73 limited slip.