I have a maxx with a Sirio .27 on it, which also has a pilot shaft. I switched to the 1/8th scale clutch setup and went with the Firioni (spelling) and it came with a clutch nut. It works fine, and the clutch bell bearings go to the end of the shaft. The only problem i had was i had the new era kit, and it had the engine sitting too far forward, so it was hitting this tranny case. I got a custom mount and it works fine now.