look for a metal tag on the axle for the rear..it should have some numbers including the gear ratio if there is a tag

 

The tag on my rear shows..."55 9 75 2A09"
the door sticker shows 19, so i presume it is a 9.75 axle with 3.55 gears. but i guess it is not limited slip, correct?
Thanks guys

oh yah.
2002f-150 supercrew. 2wd.
3.5 lift. Rear air bags.
305.75R.16 Nitto

 

Correct. Open 3.55 9.75".