A flywheel assembly includes a first flywheel having an annular wall on its outer peripheral portion, a seal plate fixed to the outer peripheral portion to form an annular space between the first flywheel and the seal plate, a driven plate arranged to freely rotate relative to the first flywheel within the annular space, an elastic coupling mechanism arranged inside the annular space which elastically connects the first flywheel and the driven plate circumferentially, and a viscous dampening mechanism. The viscous dampening mechanism is formed adjacent to the outer peripheral portion inside the annular space and has a fluid filled chamber. The driven plate includes a plurality of protrusion, each one of the protrusions extending into one of the fluid filled chambers. The viscous portion has a choke formed inside the fluid filled chamber that passes fluid while the first flywheel and driven plate rotate relative to each other.