Nut, Ring Gear Bolt
CTP380135S43 Replacement Part to Fit:  Ford 2000, 3000, 4000, 5000, 7000, (1965-1975); 2600, 3600, 4100, 4600,5600, 5700, 6600, 6700, 7600, 7700, (1975-1981); 2610, 3610, 4110, 4610, 5610, 6610, 6710, 7610, 7710, (1981 & up)  Price:  $1.80  Buyers Club Price:  $1.62