Abstract: Deals with the liquid viscous coupling(LVC) ed in 4WD cars as an axle differental.Many of the characteristics of the silicone oil is analed and mathematical models of its viscosity versus temperatUre and shear rate changes are suggestal with the aid of a computer. An intensive study on the structure,principle and properties of LVC is made.In addition,the specific hump phenomenon is elaborately dealt with. The mathematical models that deal with the torque transmitted by LVC and hump phenomen a have taken the temperature and shear rate changes into account.A prototype LVC and necessary attachments have have designed and produced,with which an experiment is made. The test results show that the above developed mathematical models suit well for LVC research, design and calculations.Some USeful conclusions and advises are given on the basis of the above mentioned experiments.