PURPOSE: To improve the durability of both the differential control clutch and the hydraulic servo mechanism thereof by temporarily restraining the execution of the differential operation permission for the purpose of improvement of the lubricating characteristics when it is detected that the front and rear wheel differential operation is to be permitted for any other purpose.
CONSTITUTION: A front and rear wheel differential controller restains the differential operation according to the vehicle driving state detected by a detecting means during all or almost running time, for example. However, since a differential control clutch is placed in the slipped state continuously for a long time and therefore the durability is reduced, the differential operation is permitted temporarily under the specified condition for the purpose of the lubrication characteristics. Furthermore, when the differential operation permission for the other purpose is detected according to the detected vehicle driving state signal, the execution of the temporary differential permission for the purpose of improving the lubricating characteristics is restrained. Thus the durability of the differential control clutch may be improved without any influence on the driving state of the vehicle.
TAKAHASHI NOBUAKI
KOJIMA MASAHIRO
KITAMURA TAKAMASA
