Question about servo replacement (gears)
 

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.

The piece on top is an adapter. It allows the manufacturer to make one servo horn (the arm) but allow it to fit a variety of servos. My suggestion would be to take a small flat blade screwdriver and work your way around the edge and try to pry it off. Don't just go at it from one spot, but pry a little on one section, move 90* and do a little more, repeat until it comes free.

Thanks klaymon. I got the adapter off. Unfortunately, the new servo is 24T and the adapter is 25T. I had to use another servo horn as my LHS does not carry those adapters.