Beefed Up Rearends

W/ a 31 spline you must get an aftermarket diff. The stocker is a 28.

Eaton makes a good one, Ford also offers one, but its not as stout. You could always go full spool :p.....

And I think Auburn offers one.

-Will
 
What is said above is true. With 31 spline axles, you must have a 31 spline differential. The stock one is only 28. I have a Ford 31 spline waiting to go in w/ 31 spline Moser axles. You may want to make sure you get a set of axles that is ABS compatable. Cause I know some of them arent. Be sure to ask about this when ordering.