Had no luck posting this in the Luthier section, so I thought I'd try here. This is the neck of an '89 Fender P Plus.
Truss rod turns, but won't adjust. It looks like this piece is beginning to extrude from the truss socket:
Does the headstock end of the truss rod push against this thing? If so, that may be why I can't get any tension on the truss rod, as it's trying to vacate the neck.
How to repair? The rod is dual-adjust.