Power transmission system for a four-wheel drive vehicle.

摘要

A power transmission system for a four-wheel drive vehicle has an automatic transmission (A) for transmitting power of an engine (E) to main driving wheels and a transfer clutch (10) for transmitting the power to auxiliary driving wheels. First and second vehicle speed sensors are provided for sensing vehicle speed dependent on the main driving wheels and the auxiliary driving wheels, respectively. A two-wheel drive switch (23) is provided for producing a two-wheel drive signal. The automatic transmission (A) uses an output signal of the first vehicle speed sensor (26) as a data representing driving conditions of the vehicle. In response to the two-wheel drive signal, the transfer clutch (10) is disengaged and an output signal of the second vehicle speed sensor (25) is selected as a vehicle speed.