Axle Width Differences:
People have asked about the widths of axle shafts to swap shafts from one axle to another.
The early 1983-1992 Ranger axles are 1" shorter than the 1993-up pieces. (Both sides) meaning that the an entire Ranger axle assembly from 1993-up is 2-inches wider than 1983-1992.
The right side Bronco II axle shaft is 1-5/8" wider than the 1983-1992 Ranger shaft. All of this additional width is in the passenger side. The drivers side shaft is the same length in either axle assembly.
On ALL Ranger/bronco II's the drivers side axle shaft is longer than the passenger side.
There is no difference between 7.5 & 8.8 axle shaft lengths provided you stay in the same year window.
As a note, if you go to a salvage yard, you'll find many left-side shafts removed from 1983-1992 Rangers and Bronco II's. These axle shafts are the same length as the axle shafts in the "Fox" (1979-1993) Mustangs EXCEPT that Ranger/bronco II shafts are five-lug and Mustangs are four lug. Ranger/Bronco II shafts are frequently "pillaged" for use in converting a Mustang to five-lug wheels.
All from here
Ford Ranger Axles - The Ranger Station