I think that I figured out your servo problem. That particular servo uses hitec style servo savers, the only ones that are included with the kit are futaba and sanwa type. You must have put the futaba style servo saver adapter on the servo and the splines are stripping. I know, because I did the same thing.
You need hitec style servo savers. I used a hitec servo saver for an Associated monster GT and it's worked well for me so far.
http://www3.towerhobbies.com/cgi-bin...?&I=LXFUL4&P=7