S&B upgraded Pitman Arm Nut fits all 2005+ Super Duty Trucks and uses all of the threads on the shaft with a surface hardened chromoly nut to be torqued to 500 ft lbs instead of 400 ft lbs. It is acceptable for this nut to be below the end of the threads on the sector shaft. 
The shaft is good to over 1000 ft lbs but the factory nut metal and width is only good for 400 ft lbs before it pulls the threads out of the nut.

***This product will require a 2in socket to install. We offer a wrench adapter, Item# 101341.