Dana 60 gear ID
There are "thick" 5.38s that can be used on 3.54/3.73/4.10 carrier, or spool. IF you want to retain your spool, you'll need to find out which it is. There is a carrier "break" , 4.10 down, and 4.56 up. (As I understand it, 4.30s are only for front axles, and take a 4.10 down carrier. So then , how can There NOT be a matching 4.30 gearset for the rear?).