Forgot to mention, Jim Carter's web site has a tech article about this, probably better written than I can do. Check it out.

And yes, the taller ratio ring-and-pinion sets only fit in the newer carriers, but any carrier from 47-72 will fit in your axle (as long as it's from a 3/4T Eaton axle).

All the Eaton axles mentioned have a rear cover AND a carrier that bolts on to the front of the axle, sort of like a F<>d 9-inch. There is also a bolt on the left side of the pinion case which is NOT a fill plug. It is a tensioner for the pinion. Unless you arre adjusting it per the shop manual, don't touch it. Hope this helps... or confuses... Good luck

Current fleet (subject to change w/o notice)
\'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run.
My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787.

Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.