Lubricating system for four-wheel drive torque transfer mechanism

In a torque transfer mechanism mounted as a separate unit on the rear end of a transmission disposed next to an engine of a vehicle, the improvement therein comprising:

• a common shaft functioning simultaneously as the output shaft of said transmission and the input shaft of said torque transfer mechanism;
• a first output shaft of said torque transfer mechanism, said common shaft and said first output shaft being supported rotatably and disposed coaxially with each other;
• a planetary gear train positioned between said common shaft and said first output shaft for selectively transmitting the rotational speed of said common shaft to said first output shaft with two different gear ratios, said gear train including a sun gear fitted onto said common shaft, pinions engaged with said sun gear, a ring gear engaged with said pinions and a carrier rotatably supporting said pinions thereon and connected to said first output shaft;
• a lubricating system including lubricating oil passages communicating with each other and formed along the central portions of said common shaft and said first output shaft of said torque transfer mechanism, pressurized lubricating oil contained within said transmission being introduced into said torque transfer mechanism through said lubricating oil passages to lubricate said torque transfer mechanism and said planetary gear train.