Synchronization Clutch

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

The transfer case is equipped with an electronically controlled clutch which is located inside the case. This clutch is used to synchronize the speed of the front driveline with the rear driveline during 2WD (2H) to 4WD (4H) shifts. The clutch consists of a transfer case field coil, a field coil housing splined to the rear output shaft, and one steel clutch plate splined to the lock-up hub. When the MSS is switched from 2WD (2H) to 4WD (4H) modes, the TCCM energizes the synchronization clutch. The magnetic field from the field coil pulls the lock-up hub clutch plate against the field coil housing. When the transfer case front and rear output shafts are synchronized, the spring-loaded lockup collar mechanically engages the 4WD drive sprocket to the field coil housing. After the shift to 4WD is completed, the synchronization clutch is deactivated.