Originally Posted by hueyhoolihan

the trouble with a distorted and notched freehub splines is that the notches are not square, they ramp up and the torque created by riding tightens the cassette onto the freehub body. it can be very difficult to get off. the displaced freehub body material can make it even more difficult that one would think.

the hard part is that there is precious little to hold on to, that doesn't also turn with the cassette, while one tries to dislodge the cassette. seeing as how the cassette must be turned slightly counter-clockwise to dislodge it, and the freehub is designed to freely turn counter-clockwise too.

the problem and it's solution are similar to the one presented by a freewheel threaded on to a hub, sans rim, and that needs to be removed. ...nothing to hold on to. ... and elusive.

sometimes, two chainwhips can be a help if the cassette has a separate small cog. by attaching one on the smallest cog and one on one of the middle cogs, and turning them in opposite directions should, with some effort allow one to dislodge the multi-cog carrier counter-clockwise.