OK guys I just orered this one
http://www.rc-monster.com/proddetail...515_1yF&cat=20 I talked to Mike and said that you dont need to flat the shaft,He said that to drill the existing hole on the pinion with 1/8" bit and then use a 4mm set screw or grub screw whatever you might call it.I'm very excited now to test it.
Brushless Jammin Truggy on NEU 1515 2.5 D on Monster mamba max with maxamps 5000mah 6s Lipo
Gorillamaxx Revo CF version on Mamba maxx ESC with NEU 1515 1Y on Maxamps 4s 8000mah Lipo