[1Bad62Pro/Street]

History
Ford began using the 8.8" axle in Rangers circa 1986 on "incomplete vehicles" aka "chassis
cabs", but the 8.8" axles only became common in Rangers with the
introduction of the 4.0L V6 in mid-1990. It began appearing in Explorers (and Mazda's Navajo
twin) in 1991. It has also been used in 4.0L Aerostars (2wd ONLY, the 4.0 AWD Aerostars,
strangely, are equipped with the 7.5" axle), From mid'84-up F-150 (Except for 5.4liter "Lightnings
and Some 4x4 Supercabs which are equipped with the heavier-duty 9.75" rear axle) '84-1/2 on
Full-size Broncos, and E-150 Econoline vans.
The 8.8 is also used in other Ford products such as Mustangs, Thunderbirds ("solid axle" '87-88
with 2.3 turbo engine and 5.0 "Sport" models), Crown Victorias and their equivelent Mercury and
Lincoln products. However, because of their different suspensions, they make undesirable
choices for swapping into a Ranger (unless you're looking to also swap to a four-link rear
suspension for airbags and such).
An IRS version also appeared in the '89-97 Thunderbird, Mercury Cougar, (Though there is also
a 7.5" IRS in some V6 cars), the Lincoln Mark VIII and finally
a very similar IRS suspension was adapted for the Mustang Cobra.
A wide range of gear ratios is available, from 3.08's up to 5.13's. An equally wide array of
differentials is also available from open carriers to limited slips to lockers and spools.
8.8" axles can have either 28-spline or 31-spline axles.
All car applications use 28-spline axles, all truck applications use 31-spline axles.
axle shafts EXCEPT Rangers, which use 28-spline axles, however even Exceptions have
Exceptions, FX4 Rangers 99-current with 4.10 or 4.56 axle ratios are built with 31-spline axles.
Gear sets are interchangeable between axles, regardless of the spline count. Differentials,
however, are not.