Fan was super crusty so I picked up a replacement, SPAL part number 3010.3018 / VA32-A101-62A. Wasn't sure what the little sealed box is on the factory fan is so I spliced in the new fan after it. If replacing with this fan note that you will not be able to reuse the factory hardware, the mounting holes in the new fan are too big so you'll want to pick up some bolts and nylon lock nuts.

I decided to dissect the old fan. The sealed bearings were actually still good, all the crust was built up between the sealed fan motor housing and fan blade assembly, which seems to be just press fit onto the shaft. I removed mine by drilling out most of the shaft. If one were so inclined, you could drill and tap it and and reattach the fan after cleaning.