Modular surgical instruments with contained electrical or mechanical systems

A surgical instrument, comprising:

• a handle module including at least one handle having a gripping surface;
• and
• a drive assembly configured to be selectively removable from the handle module, the drive assembly including:
• a housing;
• an elongated shaft defining a longitudinal axis extending from the housing;
• an end effector disposed at a distal end of the elongated shaft, the end effector including a pair of jaw members, wherein at least one of the jaw members is movable relative to the other jaw member between an open position and a closed position;
• a drive member extending at least partially though the elongated shaft, the drive member operably coupled to the end effector and configured to induce movement of the jaw members between the open position and the closed position in response to longitudinal reciprocation of the drive member;
• a knife extending at least partially through the elongated shaft;
• and
• a seal member operatively coupled to the elongated shaft and configured to prevent contaminants from entering the elongated shaft.