Gearing

[Twisted_Steel]

Is there a specific trim/tow package that Ford used to differentiate between a L/S or open geared rearend?

 

[adsm08]

Nope. FX4 and FX4 LII will always have the L/S rear, but beyond that, it's an option, and from what I can tell its one that not a lot of people went for.

I'm not sure that you could get it below the XL package though.

If you are looking for a L/S rear just check the tag. It will read something like "3 L 73" for a limited with 3.73 gears.