A part of engine torque is used to overcome the interior friction and to accelerate engine inertia. To enhance the driveability at the clutch slip control of AMT(Automated Manual Transmission) or parallel type hybrid system, it is important to know the exact drving torque of clutch. In this study, engine friction and rotational inertia are estimated by using LMS(Least Mean Square) method with vehicle test result. To verify the validity of method, the performance of vehicle is simulated with adjusted parameters. The test result and simulation result show the similar trend.