Explorer 8.8 you get bigger shafts (31 spline) and tubes and disc brakes, BUT, you gotta do some welding/fabbing to get them to fit and they are 1.5" wider than Ranger 8.8s.
With a Ranger 8.8 you will upgrade the ring ang pinion, shafts are actually the same from 7.5 to 8.8. It's also a simple bolt on.
That said, you could buy my 8.8, 4.10 geared
My neighbor lives in Hamden CT (has a vacation home next to me) and he'll be up in a few weeks...you could even buy my front D35 to regear to 4.10 and have an 8.8 out back!