you have to shave the fins down to fit inside the plastic housing its a tight fit but it works, and easier and better solution would be a FLM tranny case
one of these days ill get one for my slash. i switched to mod1 gearing and can run 40/12 through 40/17 i usually run a 40/14 which is silly silly fast.
http://www.rc-monster.com/forum/atta...8&d=1214712244