Full-time transfer case with synchronized dual planetary gear reduction unit

摘要

A power transfer system is disclosed for a four-wheel drive vehicle operable for permitting a vehicle operator to select between various full-time and part-time four-wheel drive modes. The power transfer system includes a transfer case equipped with a dual-planetary gear reduction unit and a synchronized range shift mechanism operable for permitting the vehicle operator to shift on-the-fly for establishing full-time and part-time high-range and low-range four-wheel drive modes. The transfer case is also equipped with an electronically-controlled slip limiting/torque-biasing arrangement including an interaxle differential and a transfer clutch operable for controlling the magnitude of speed differentiation and torque biasing across the interaxle differential.