Possibly the most troublesome part on the Super Duty Dana 50 and 60 is the factory unit bearings. Along with the vacuum-assist hubs, the stock unit bearing outers are known to wear more rapidly when equipped with larger tires and heavy off-road use. The Free-Spin kit from Dynatrac replaces the unit bearings with a more traditional full-float spindle. In addition to being serviceable (factory unit bearings are not) the Free-Spin kit spaces the bearing set to better handle the heavy loads of the 3/4- and 1-ton trucks.
