Drive axle with internal air shift mechanism

An air actuated shift mechanism is housed within a drive axle housing and can be used to actuate a two-speed shifter, or it can be used to actuate a differential locking mechanism. The air actuated shift mechanism includes a lock member and an engageable member that is selectively engaged by the lock member. When the lock member and engageable member are in an engaged position, a first axle function is provided such as a low speed or a locked differential condition. When the lock member and the engageable member are in a disengaged position, a second axle function is provided such as a high speed or an unlocked differential condition. A shift member moves one of the lock member and the engageable member to provide the engaged position, and an air actuated piston controls movement of the shift member.