I'm working on a SPECIALIZED "ROCKHOPPER" MTB that's 3 to 4 years old. The rear hub itself has SPECIALIZED on it and I must assume that this rear wheel unit is standard issue & original. The freehub is sticky, needs lubrication in that it randomly likes to stop working &dumps the chain. My problem is that the freehub seems to require more than a 10mm allen wrench for removal. I do not know the actual brand of the freehub assembly... the cluster has Y11 & YJ identifiers on them. Does anyone know what size allen is required & would know if this freehub can even be serviced? El mucho kudos for any assistance/insight.