Transmission system for vehicle

An automatic transmission system for a vehicle, comprising:

• an input shaft,
• an output shaft,
• a plurality of shift gear trains having different gear ratios, said shift gear trains including drive gears mounted on said input shaft and driven gears mounted on said output shaft, said driven gears meshing with said drive gears respectively to form said shift gear trains respectively,
• synchronizing mechanisms for synchronously engaging said drive gears with said input shaft respectively and for synchronously engaging said driven gears with said output shaft respectively,
• a plurality of actuators for respectively operating said synchronizing mechanisms for shifting said shift gear trains;
• a torque converter for amplifying an engine power having an output element for outputting said engine power;
• a bypass clutch for transmitting said engine power from said input shaft to said output shaft during shift operation of said shift gear trains;
• an input clutch for connecting and disconnecting said output element of said torque converter with said input shaft;
• and
• a shift controller for automatically controlling said actuators, said input clutch and said bypass clutch to shift said shift gear trains according to a vehicle running condition;
• wherein, when said shift controller up-shifts said shift gear trains from a lower-side shift gear train to a higher-side shift gear train, said shift controller engages said bypass clutch to transmit said engine power from said input shaft to said output shaft through the bypass clutch, before disengaging said synchronizing mechanism for the lower-side shift gear train.