How can I verify that I have limited slip rear?

What is the axle code suppose to read on the door tag?

Thanks,
Sean

I only ask because in previous vehicles that I have owned there was always a tag on the differental cover that stated to use friction modifier when changing the fluid and there is not a tag like that on mine. There is a tag that says to use the synthetic fluid and the other tag has a bunch of numbers/letters on it that doesn't make much sense to me.

 

Sean, the codes should be as follows:

19 = 3.55 Non-Limited slip
18 = 3.08 Non- Limitd slip
H9 = 3.55 Limited slip
B6 = 3.73 Limited slip

At least for my F150, I'd assume it's the same for S'Crew.

ID Label located on the pillar visible when driver's door is open. Look along the bottom of the label for axle codes.

 

What color should the oil be in these differentials? Mine is gray. I checked in the "other drivetrain" section of this board and others have reported this as well. The dealer says yes that is correct. It should be grey and as long as it is not milky (ie water in the oil).

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2001 Silver XLT 2x4 SuperCrew (Gen II) 5.4L 3.55LS Tow Package (now with 2.02" rad) & Cab Steps

Mods: K&N Filter, LoRider by Raider Fiberglass Tonneau, Stull Billet Grille (Black)

Tow: 31FT. Glendette Deluxe Camper Trailer