In this study, the torsional dynamics of an automotive drivetrain equipped with a three cylinder spark ignition engine and a five speed manual transmission were investigated for two configurations: a conventional single mass flywheel (SMF) and a dual mass flywheel (DMF). A detailed powertrain model featuring 44 torsional degrees of freedom was developed in AVL EXCITE™ PowerUnit to evaluate the influence of the DMF on vibration attenuation across a wide spectrum of operating conditions, including engine start-up, idle, vehicle launch, creep, drive and coast speed sweeps, tip in and back out, and engine stop. Experimental validation of the simulation results was performed for the 4th gear speed sweep of the SMF configuration. The results indicated that the DMF significantly reduced the torsional fluctuations transmitted to the gearbox in quasi-steady conditions such as idle, creep, drive and coast speed sweep. In transient conditions, however, the system exhibited more complex behavior. During start-up, stop, and launch, an increase in drivetrain oscillations and vehicle longitudinal acceleration fluctuations was observed. In contrast, in tip-in and back-out maneuvers, the DMF led to a noticeable reduction in input shaft oscillations of the gearbox. Overall, while the DMF improves powertrain torsional behavior across most quasi steady conditions, certain transient events—particularly engine start up—highlight limitations in its dynamic isolation capability. Furthermore, the altered inertia distribution and increased crankshaft angular velocity fluctuations necessitate additional durability and NVH assessments of cranktrain components, including the crankshaft, to ensure optimal DMF performance.