I have replace a couple of time the upper aluminium gear in the tranny of my savage flux and i want a more durable gear i have two choice titanium upper gear but i do but the kit for 123$
http://www.gpmparts.com/shop/hpi-sav...-90008067.html
or just the delrin 18-23 upper gear for 10$
http://www.gpmparts.com/shop/hpi-sav...-90008062.html