the shift fork assembly 200 includes a body 202 having a through passageway 204 which is sized to just freely rotatably receive the shift rail 180 at each end of the shift fork body 202 is a helical cam 206 the helical cams 206 are correspondingly disposed such that the axial distance from corresponding points on their surfaces is just slightly less than the distance between the inside surfaces of the rollers 194 an axially extending face or shoulder 208 which represents a discontinuity in the helical cams 206 acts as a positive stop in one direction of rotation as it engages one of the rollers 196 the shift fork assembly 200 also includes an obliquely extending web 210 which terminates in a discontinuous semi circular channel or groove 214 the semi circular channel or groove 214 receives and engages the flange 108 of the clutch collar 100 such engagement inhibits rotation of the shift fork assembly 200 accordingly as the shift rail 180 and the cam followers or rollers 194 rotate the shift fork assembly 200 and specifically the clutch collar 100 translate axially and bi directionally such translation effects selective engagement of the clutch collar 100 and selection of high gear neutral or low gear as previously explained referring now to fig2 4 and 5 the transfer case assembly 16 also includes an electromagnetically actuated disc pack type clutch assembly 220 the clutch assembly 220 is disposed about the output shaft 60 and includes a circular drive member 222 coupled to the output shaft 60 through for example a splined interconnection the circular drive member 222 includes a plurality of circumferentially spaced apart recesses 226 in the shape of an oblique section of.