holycow- there were 2 types of oneways. The original one had more parts (the centre axle and the "metal claw-like thingy" were separate parts). If you have this one, it doesn't fit the RW pulley. The newer ones have the axle & claw thingy machined from one piece, IIRC. I don't remember exactly when the one-way was changed, but is was a loooong time ago, before the RW pullies came out.
If you have the newer version with one-piece centre, chances are you have the wrong pulley (meant for front diff).