i'm familiar on the purpose of this part. i was replacing u joint and i broke a piece off the retainer yea i know rookie mistake. how important is this piece to be there, there is still allot of teeth to remove this part if needed. i have the merc I-R outdrive that piece that broke off just sits in a rubber ring is there a seal issue.
in the picture the red colour represents the piece broke off
in the picture the red colour represents the piece broke off