8.8 swap

the ranger is a bit more narrow, but they used 28 spline axles as opposed to 31 in the explorer. and as far as i can tell from shopping around, the biggest majority are open carriers, where the explorers are mostly limited slip.

as far as i can see, some early 2000s fx4 models used 31 spline axles, 4.10 gears, and a torsen limited slip, but you have to do some research and be specific when youre shopping.

explorers aren't the only diffs you can use, it seems they're just the most common when it comes to finding the whole package of desirable parts all together. if you can get the beefier axles, good gear ratio, limited slip, plus a disc brake upgrade all together for a couple hundred dollars its pretty much the best deal even if you do wind up having to shorten an axle.