Interaxle differential restriction device for vehicle four wheel drive systems

A vehicle four wheel drive system including engine means having output shaft means extending transversely of a vehicle body, transmission means having an input member and an output member extending transversely of the vehicle body and speed ratio changing means provided between the input and output members, said transmission means being disposed adjacent to said engine means in the transverse direction of the vehicle body, said input member being connected with the output shaft means of the engine means, planetary type inter-axle differential gear means having an input member and two output members, said input member of the inter-axle differential gear means being connected with the output member of the transmission means, first inter-wheel differential gear means provided on first wheel axis means and connected with one of said two output members of the inter-axle differential gear means to drive said first wheel axle means, second inter-wheel differential gear means provided on second wheel axle means, transfer gear means connected with the other of said two output members of the inter-axle differential gear means to drive said second inter-wheel differential gear means, said inter-axle differential gear means and said transfer gear means being located on said first wheel axle means, said first inter-wheel differential gear means being located at one side of said inter-axle differential gear means adjacent to said engine means in the transverse direction of the vehicle body, said transfer gear means being located at the other side of the inter-axle differential gear means opposite to said one side where the first inter-wheel differential gear means is located, differential restricting means provided coaxially with said inter-axle differential gear means and the first inter-wheel differential gear means and located at a side of the transfer gear means opposite to said first inter-wheel differential gear means in the transverse direction of the vehicle body, said differential restricting means including first clutch disc means connected with said transfer gear means and second clutch disc means opposite to said first clutch disc means and connected with said one output member of said inter-axle differential gear means, and means for urging said first and second clutch disc means into power transmitting engagement with each other.