1. One of the hubs wasn’t engaging the axleshaft when we spun the hub/rotor. This can often be attributed to improper hub assembly so it didn’t immediately raise a red flag. Sometimes just pulling an external-body hub off and reinstalling is enough to fix the issue. In our case, the splines in the driver-side hub were stripped and damaged. Rebuild parts are available from Warn, but this breakage proved only the beginning.