As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER CLEANING OF HUB AND NDT, HUB WAS CORRODED BADLY ON THE INSIDE OF THE HUB ONLY. THE CAUSE OF THIS IS THE USE OF NON-APPROVED AUTO GREASE. SUBMITTER STATED IF THIS WAS NOT FOUND, IT IS POSSIBLE A CRACK AND FAILURE OF THE HUB WOULD OCCUR.