I have Vaterra TwinHammers with a busted steering servo. I got a replacement servo but the original one has additional gear mounted on the smaller gear wheel (I am new to R/C so I do not know the proper wording). What's the best way to remove the gear? I do not have such a small puller. Photo shows the top gear mounted on the smaller servo gear.

i1215.photobucket.com/albums/cc506/drabina2010/For%20sale/servo_zpsimqi0brj.jpg

Sorry, can't post a live link because I do not have enough posts.