You'll need the following:
http://www3.towerhobbies.com/cgi-bin...?&I=LXXF43&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXXF44&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXXF49&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXXF52&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXXF46&P=7
I'm might be missing some thing like the reverse gears and shifting mechanism. The best thing to do is just go to ebay and buy a used 3906 emaxx tranny, steel idler gears(UE have them in stock) and just remove the first and reverse gears.