I don't want to swap in an Explorer axle. although a disc conversion would be nice, I'd have to swap out the master cylinder, as the Ranger's isn't calibrated for rear disc. What's more, if I swap in anything different than a 4.10, and end up having to swap out the ring gear and pinion, that means taking it to a shop and getting everything adjusted just right. If I'm going to do an axle swap, I want to avoid going into the diff.
I can find an entire FX4 axle, as well as an FX4 Level II axle at a wrecker here. They want something like $350 - $450, depending on the model. What are these things actually worth, used? That is more money than I wanted to spend...