For threaded shafts...
The driven section (part/piece) must turn "faster" than the driver to unscrew. In other words, in the same direction of rotation that the shaft turns. Example, the Hyd Pump on the JD6600 combine. Whack the pump shaft in the same direction of shaft rotation to loosen.
The driving section (part) will be opposite the direction of shaft rotation to unscrew.
Try it with a bolt and nut.