Abstract: The present invention provides a system and method for releasably retaining at least one coil spring. The present invention utilizes a circumferential castellation formed within a housing operable to receive within the notches formed by the castellation a complimentary number of fingers formed from a retainer plate. The retainer plate is operable to hold the coil springs in compression and is fixed in place by an internal snap ring disposed within an inwardly facing circumferential grove formed on the radial inner side of the protruding blocks or dentils formed by the castellation.

Abstract: The present invention relates to a torsional damper for an electrically variable transmission. The torsional damper is equipped with a hydraulically actuable lock-out clutch to selectively directly couple the engine to the input shaft of the transmission. The electric motors provided with the electrically variable transmission can serve to effectively cancel out engine compression pulses when the springs of the torsional damper are locked out. During higher speeds the centrifugal loading placed on oil in the torsional damper increases, which may cause the lock-out clutch to inappropriately engage. The present invention hydraulically balances the hydraulic actuator (or piston) driving the lock-out clutch to appropriately regulate lock-out clutch engagement.