Originally Posted by
icemilkcoffee
Pic assist:
This is clearly not a Shimano freehub.
You are most likely out of luck. Time to look for a new hub or wheel or wheelset.
That back spline interface and internal thread sure looks a whole lot like the link I posted in #6 above. What may not match is what appears to be the cog splines removed close inboard, and possibly cog spline width. But says for SRAM/Shimano. And says fits Fulcrum racing wheels.