An axle assembly comprising: a differential assembly that includes: an outer housing that has a first side gear that is rotatable about an axis; an inner housing that is at least partially received inside the outer housing; a gear reduction unit that operatively connects the outer housing to the inner housing, wherein the gear reduction unit includes a spider that is fixedly disposed on the inner housing, a second side gear that is rotatable about the axis, and a pinion gear that is rotatably disposed on the spider and that meshes with the first side gear and the second side gear, wherein the second side gear has a second side gear spline that is received in a second side gear hole, and the spider has a spider spline that is received in a spider hole; a coupling that is moveable between a first position in which the coupling inhibits rotation of the first side gear with respect to the second side gear and a second position in which the coupling inhibits rotation of the spider with respect to the second side gear, wherein the coupling has a first coupling spline that meshes with a spline and a second coupling spline, the second coupling spline meshes with the second side gear spline but not the spider spline when the coupling is in the first position, and the second coupling spline meshes with the second side gear spline and the spider spline when the coupling is in the second position; and a differential nest that is at least partially received in the inner housing; and a first axle shaft and a second axle shaft that extend from the differential nest and are rotatable about the axis. a differential assembly that includes: an outer housing that has a first side gear that is rotatable about an axis; an inner housing that is at least partially received inside the outer housing; a gear reduction unit that operatively connects the outer housing to the inner housing, wherein the gear reduction unit includes a spider that is fixedly disposed on the inner housing, a second side gear that is rotatable about the axis, and a pinion gear that is rotatably disposed on the spider and that meshes with the first side gear and the second side gear, wherein the second side gear has a second side gear spline that is received in a second side gear hole, and the spider has a spider spline that is received in a spider hole; a coupling that is moveable between a first position in which the coupling inhibits rotation of the first side gear with respect to the second side gear and a second position in which the coupling inhibits rotation of the spider with respect to the second side gear, wherein the coupling has a first coupling spline that meshes with a spline and a second coupling spline, the second coupling spline meshes with the second side gear spline but not the spider spline when the coupling is in the first position, and the second coupling spline meshes with the second side gear spline and the spider spline when the coupling is in the second position; and a differential nest that is at least partially received in the inner housing; and an outer housing that has a first side gear that is rotatable about an axis; an inner housing that is at least partially received inside the outer housing; a gear reduction unit that operatively connects the outer housing to the inner housing, wherein the gear reduction unit includes a spider that is fixedly disposed on the inner housing, a second side gear that is rotatable about the axis, and a pinion gear that is rotatably disposed on the spider and that meshes with the first side gear and the second side gear, wherein the second side gear has a second side gear spline that is received in a second side gear hole, and the spider has a spider spline that is received in a spider hole; a coupling that is moveable between a first position in which the coupling inhibits rotation of the first side gear with respect to the second side gear and a second position in which the coupling inhibits rotation of the spider with respect to the second side gear, wherein the coupling has a first coupling spline that meshes with a spline and a second coupling spline, the second coupling spline meshes with the second side gear spline but not the spider spline when the coupling is in the first position, and the second coupling spline meshes with the second side gear spline and the spider spline when the coupling is in the second position; and a differential nest that is at least partially received in the inner housing; and a first axle shaft and a second axle shaft that extend from the differential nest and are rotatable about the axis.