Abstract: The full load running in capacity of three corrosive running in agents and the anti seizure load class were comparatively investigated on a CL 100 gear tester. The results indicate that severe seizure occurred for the gear pairs of AISI 1045 steel and 20CrMnTi steel which were subject to single full load running in testing in the presence of abrasive containing running in agents. The single full load running in was realized in the presence of corrosive running in agents, and the anti seizure capacity of the gear which was subject to running in in the presence of corrosive running in agents was increased by one load class. Thus corrosive running in agents could be promising candidates for gear running in.