I will post a photo when I figure how to post online.
The corrosion is only surface.I had an ac engineer take a look ,he wasn't overly concerned but recommended a cleanup &crack test. His concern was how the thread was formed, If it was machined rather than rolled? There is potential for a crack to form.If the threaded portion is replaceable ,easy fix.His suggestion is to convert to a threaded plug with a male rod end.
Has this been done by any any builders?