[Reaper450128]

I know I'm delving into an area few of us have any experience with, but I have to ask the question anyway so I can get this done. Perhaps someone with a Subaru tech friend or a Subaru tech could answer this: I'm part way through the transmission disassembly process now, I've taken out most of the internal components, and the next step in the service manual tells me to apply compressed air to remove the low & reverse piston. Now, I'm fairly certain I've got the right point to apply the pressure to, but I'm not clear on where the piston is going to come out from, and so far I've been unable to get the compressed air to have any effect, it's been blowing off a small amount of air from somewhere in my blowgun. So, what am I missing?