[creeper]

That looks like an oilite bushing that disintegrated. When my pilot bearing failed and chewed up the shaft the OEM units were backordered for several months already and no aftermarkets were available, so I cleaned it up with emery cloth and slapped it back together with a bushing. It lasted 50k miles before the bushing turned to dust exactly like that.

As soon as the symptoms came back I pulled it apart again. Due to the likelihood that some extra wear had already occured I gambled and just dropped a $125 aftermarket shaft in from the front with the T56 standing in a bucket. No issues so far.

I believe my issue was likely caused by a missing dowel pin allowing a slight misalignment, because I never pulled the transmission in by the bolts and the bearing failed with very low miles on it