In a power transmission module a snap-ring is fitted inside a groove of a clutch drum. When a hydraulic pressure is applied at one end of a clutch piston it presses against a clutch pack and an end plate. The end plate then presses against the snap ring, which reacts against the groove of the drum. It is required to estimate the pressures, deflections and stresses of the various components when a maximum hydraulic pressure acts. A non-linear large deflection analysis of the snap-ring, which fits into the groove, is performed. A number of contacts between the different deformable bodies, i.e. end plate and snap ring, snap-ring and the groove, etc. are resolved for equilibrium.