<p>Lubrication state decided by oil film thickness varies with system relative displacement, affecting system response reversely through dynamic parameters. Therefore, a cycle is established in the meshing behavior due to the interaction between the lubrication state and system response, which is necessary for the dynamics of the wind turbine’s transmission mechanism. Wear controls the oil film thickness and affects the dynamic factors to join the cycle, and indirectly impacts the system response as a result. With consideration of the instantaneous lubrication state, the bidirectional effects between the lubrication state and system response are captured, leading to fundamentally different from the previous model with a single effect of lubrication on vibration caused by the fixed lubrication state assumption. The instantaneous lubrication state definition also comprehends the mechanism of wear on system operation better. Experimental verification is conducted, confirming the dynamics of the worn surface, and the results demonstrate that considering the instantaneous lubrication state aids in the practical detection of wear.</p>