<p>This study investigates electromechanical coupling phenomena in an electrified drivetrain through the development of a hybrid model that integrates analytical formulations with Finite Element Method (FEM) results. By accounting for the nonlinearities inherent in Interior Permanent Magnet Synchronous Motors (IPMSM) and those arising from gear backlash, the model provides a comprehensive framework for simulating torsional vibrational behavior. The motor formulation, derived from magnetic co-energy, captures complex effects such as ferromagnetic saturation and position-dependent torque ripples, while the inclusion of Hertzian-contact theory through FE enables an accurate representation of time-varying gear mesh stiffness (TVMS). Modal analysis of the system reveals that the transition from a purely mechanical model to a coupled electromechanical one introduces stable, low-frequency modes where electric and mechanical state variables interact, while high-frequency modes remain largely decoupled. The dynamic behavior under varying operating conditions confirms a significant interaction between the subsystems in the superharmonic resonance regime. Specifically, nonlinear dynamic analysis demonstrates that the electromagnetic torque exhibits harmonic and subharmonic components characteristic of gear meshing, indicating that neither the control system nor torsional shaft compliance effectively filters these oscillations. These findings emphasize that accurate theoretical models of electrified drivetrains must account for fundamental torque harmonics associated with gear-meshing frequencies to capture the dynamic response of the system.</p>