Check the big bearing behind the big sprocket . Pricey if you go through NH ($ 1200 +)  Last one I did about 5-6 years  ago local bearing shop was $250 . If the casting is shot you cant just  twist   a bearing in . Than you would need to get the whole thing from NH . The castings can get rotten .

Good spread pattern  .  They  dont like pen pack , unless you really tear it apart loading . if its wet pen pack that helps some .I had a green one and NH one years ago .