A transfer case includes a two-speed range unit, a friction clutch, an
actuation mechanism and a control system. The actuation mechanism
includes an electric motor, a geartrain driven by the motor, a range
actuator assembly and a mode actuator assembly. The range actuator
assembly includes a driveshaft driven by the geartrain, a cam driven by
the driveshaft and a shift fork having a follower retained in a groove
formed in the cam and a fork engaging a shift collar associated with the
range unit. The mode actuator assembly has a face cam with spiral cam
surfaces and a control gear with radially-moveable rollers engaging the
cam surfaces. The control gear is rotatively driven by the geartrain. The
face cam is axially moveable for controlling engagement of the friction
clutch. An anti-rotation mechanism limits rotation of the face cam in
response to continued rotation of the control gear.