The sleeve should have tabs on the side that you can pry up a little to slide it off. Actually, I can see them in your picture.Great write up! I am doing this right now, but have a question. I got my Sony stereo from Quadratec and it came with the "sleeve" already attached to the radio. I'm guessing for ease of shipping. To get the sleeve to set in the adapter, I'm thinking I need to remove the sleeve? That way I can get those metal tabs to bend down to grip the adapter. Does that make sense? if so, how do I remove the radio from the sleeve.