OK, here's the deal: Everybody here can agree that a rebuilt unit is better than a used one. Hell, you could even BUY a rebuilt one if that's what you want! But for those of us on a budget, You may want to spend less on a good used one! I spent years buying rears at swap meets and selling them as used units. The OP asked for a simple way to tell if it needs rebuilt. I offered it. I used to take two shortened axles with handles welded to them to test every rear I bought. Doing the axle test will tell you three things: #1.Either it's DEFINATELY blown and needs rebuilt or #2 It's starting to go and should be rebuilt, or #3 It's probably good and can be run as is.
Could you rebuild one that tested good? Certainly! Would that be better? If you have the money SURE!
But just like buying a 50k mile motor from a wrecked car, if it has good compression and oil pressure you could probably run it without spending any money on it. And if it does fail later? rebuild it then!
Every rear I ever tested gave me great service without having to spend money on a rebuild.
BTW you do NOT have to remove the center thrust pin to run green bearings but you DO have to have them to run stock bearings. If they are in, leave them be. (Before the trolls start, This has been verified by Dr Diff)
