I had the same prob with the pass. side.... turns out there was a clip retainer on the inside.... that holds the turn piston in place. Check to see if the C-clip is in place.... it's REALLY easy to take these apart.. just don't be scared

. Seriously ... at first I was reluctant to do it... but then I said Ah Fawk it!. Once I had it open.. I got a better understand of how it works. If this isn't the problem .. then Keep trying what
X01VTEC said to do... eventually the gear will pop back into place .. (I am not responsible for any damages that may occur when trying this... hehe.. felt I had to put this in). Good luck bro.
Ceasar