Turns out that the end of the retainer bolt had indeed broken off, possibly the result of the shaft being sweated/galled into the heat on the opposing side!! After a solid 15 minutes of beating on the shaft with a 2.5lb sledge I saw dimples appearing in the carrier, I drilled two relief pockets for the offending bits to come out, took a solid 45 minutes more beating for the shaft to clear that first gear, then it dropped out like it should. Any ideas where to source a replacement gear and shaft? Oh ya, also hammered the crap out of the brass shim so I’ll need one of those too!!!