all Explorers will have an 8.8 under them. You're looking for 95+ so you get the disk brakes. check for ratio before buying, don't settle for anything less than a 4.10, and don't pay any more for a v8 model since they are identical inside (only the brackets outside change and you're going to cut them off anyway). oh, and make sure you get the calipers from some explorer (not necessarily the one with the 4.10s) since the core charge on them is huge.
as for Jeeps,
and the 8.25 has a pronounced flat section across the bottom of the differential.