I asked my differential guy who just finished up rebuilding my new 3.40, 12 bolt that I got today. He said the 2.76, 3.08, 3.40 or 3.42 use the same carrier, and that one is now remade but expensive. It has been hard to find in the past. the 2.56 and 2.73 use another carrier. The 3.73, 4.11, 4.56, 4.88, and 5.13 use another carrier.
It is a little more complicated than this and so as HRL said the set-up is best left to the guys in the know.
some thick, some too thin carriers: (mismanufactured) were made sometime ago (70's) that got out into the system. You should not have to worry about those now.
trucks and autos:
diff's have different offsets.
I'm just passing on what he knows.
