A surgical instrument may include an end effector (1202), an input drive shaft (1270), a closure drive (1232), and/or a firing drive (1248). The end effector may comprise a jaw assembly including a first jaw member (1204) and a second jaw member (1206). The end effector may comprise an I-beam member axially translated between a proximal position and a distal position within the end effector. In one embodiment, the input drive shaft may selectively engage the firing drive and/or the closure drive. In one configuration, the closure drive is threadedly engaged with the firing drive allowing the input drive shaft, during a firing stroke, to simultaneously move the closure drive and the firing drive until the closure drive is disengaged from the firing drive. On a reverse stroke, the closure drive may be reengaged with the firing drive.
