A vehicle driveline comprising a primary drive system including at least one primary drive wheel and an auxiliary drive system including at least one auxiliary drive wheel is disclosed. The vehicle driveline may further comprise a system for idling the auxiliary drive system. The system may include at least one wheel disconnect device for selectively connecting and disconnecting the auxiliary drive wheel from the auxiliary drive system and a power transfer unit for selectively engaging and disengaging the auxiliary drive system from the primary drive system. The power transfer unit may include a multi-plate clutch in series with a dog clutch.