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Vibro-impacts of gear pairs in a torsion system inherently occur under the steady state torque input condition since clearance type nonlinearities are related to the torsional vibration induced by the firing stroke of an engine. In order to investigate the dynamic characteristics of gear rattle, front engine and front wheel drive configuration of the manual transmission is investigated under both wide open throttle and coast conditions. This configuration is examined using 6 degree-of-freedom system model, embedded by the relevant nonlinearities such as multi-staged clutch dampers, gear backlash and drag torques. This article focuses on the relationship of vibro-impacts with key parameters of clutch dampers, where the gear rattle phenomena are defined by 'sing-sided', 'double-sided' and 'no-impact' along with different clutch dampers. Thus, the mathematical model of the multi-staged clutch dampers is developed by including the asymmetric transition angles and pre-load effect. Based upon this nonlinear model, three real-life clutch dampers are employed and simulated results are compared with limited experimental measurements conducted on a vehicle. Also, the dynamic characteristics of gear motions under the coast condition are investigated. This coast condition is explained corresponding to different input torque conditions and its simulations show the main reasons of vibro-impacts induced by the clutch stopper well. Finally, modified clutch damper concepts for rattle-free transmission are proposed along with dynamic clutch design guidelines. [ABSTRACT FROM AUTHOR]