I see you have the old school slipper. Look in to upgrading that to the new style slipper. Best darn upgrade you can get for a rustler. Parts needed for the conversion:
http://www2.towerhobbies.com/cgi-bin...?&I=LXKMG7&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXKMG3&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXNMN8&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXDGG3&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXD121&P=7
http://www2.towerhobbies.com/cgi-bin...?&I=LXJF37&P=7
http://www2.towerhobbies.com/cgi-bin...=++&search3=Go
Exploded view from the traxxas website.
http://www.traxxas.com/products/elec...pede_trans.pdf
Edit: btw that comes out to $29.43 worth of parts. May seem like alot but its well worth it for someone that has gone brushless. If you prefer not to do the upgrade then plan on replacing many shafts, trans gears, and diff gears. Like I said before. Best upgrade I ever did for my rusty/pedes.