Abstract: A transfer case for a four wheel drive vehicle providing a central shaft defining a first output concentrically surrounded by a forward high/low drive range gear set and an aft dual planetary inter-axle differential gear set. A range clutch collar is disposed between the gear sets for selectively providing four wheel drive low range, neutral, and full-time four wheel drive high range. Likewise, a mode sleeve is disposed between the gear sets for selectively locking the differential gear set when the vehicle is shifted into its four wheel low range. Inner and outer relatively rotational drum housings surround the aft dual planetary differntial gear set for defining an annular viscous fluid coupling chamber therebetween.

Abstract: A transfer case for a four wheel drive vehicle providing a central shaft defining a first output concentrically surrounded by a forward high/low drive range gear set and an aft dual planetary inter-axle differential gear set. A range clutch collar is disposed between the gear sets for selectively providing four wheel drive low range, neutral, and full-time four wheel drive high range. Likewise, a mode sleeve is disposed between the gear sets for selectively locking the differential gear set when the vehicle is shifted into its four wheel low range. Inner and outer relatively rotational drum housings surrounded the aft dual planetary differential gear set for defining an annular viscous fluid coupling chamber therebetween.