The crush sleeve is the one that fits between the bearings. There probably won't be a spacer between the pinion flange and the front pinion bearing cone. The crush sleeve is a one-time use item, so it might be necessary to procure a new one if you're reassembling a rear end with used parts. I hope you checked the tooth contact pattern before disassembly, as it's possible to build in a gear noise unless you get lucky and assemble the gears in exactly the same relationship as they came apart.
Jerry

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