Originally Posted by SemperFiDevilDog
The 3.31 rear axle is STANDARD on ALL (4x2 & 4x4) Optional 3.73
Originally Posted by SemperFiDevilDog
The EL's come Standard with the 3.73 rear axle
Since SemperFiDevilDog posted the 3.31 & 3.73 question about a dozen times, I looked for a 2008 build sheet. I had to register at blue oval forms to down load one. Here's the statement for the 2008's, and yes its different from 2007.
3.31 axle was made standard on 4x4 Expedition (non-EL), similar to 4x2. 3.73 axle is available as an option (X16)
Basically, per the order guide 3.31 (X15) is standard for non-el 4x2 or 4x4. The 3.73 (X16) is standard on EL's and SSV (Special Service Vehicles - Police etc). The 3.73 (XH6) LIMITED SLIP, is only available on the (17L) EL Limo Prep package.