Not a how-to but just general information please add if you feel I've missed anything, just got done with a similar swap. You can use either of these on your ranger up to 04 not too sure on upwards. But you can use either BW1350 or BW1354, the 1354 is a stronger version of the 1350 and linkage is setup slightly different and will require some modification to get it to work right on your 91+ Ranger but the 1354 is a direct swap along with bolting the linkage up. Beware that when unbolting your transfer case that transmission fluid will pour out so watch yourself. And you can use High-temp RTV instead of hunting down a gasket when bolting the new transfer case on. Easy swap but may want a buddy to help you push the other case onto the output shaft and aligning it up.