I believe that if you were to make ball mill Al turnings with a wax, or Vaseline type substance, as the Al powder formed, it would not be able to get an oxide coating on it making it significantly more reactive. As it is suspended in a solvent, the waxy layer would dissolve leaving Al exposed to the chlorine/HCl.

Did you try heating the solvent to a fairly high temperature to boil off any water that might be present? Perhaps the solvent wasn't totally dry and caused the Al to continually form an oxide/hydroxide layer making it so the reaction didn't continue as fast as it should have? Also if the chlorine were messing with the water, like it does; Cl2 + H2O = HCl + HOCl, it may have been really good at putting on an oxide layer.

I don't know, but personally I would maybe try treating refluxing toluene/xylene with Al powder that has been made with an soluble oil coating, or with a bit of dry HgCl2.