Apparently, you have a split case differential that EZGO used from 1986.5 through 1987.
Attached are the Parts and the service manuals for it.
Looks like the threaded shaft is actually the armature shaft in both manuals, but if it is only mechanically coupled to the armature shaft, heat might loosen it.
Doesn't look like you could hurt the armature at this point.
BTW: Motor removal and disassembly instructions in service manual.