Automatic dual-clutch transmission

An automatic dual-clutch transmission comprising:

• a first input shaft and a second input shaft arranged coaxially,
• a first output shaft and a second output shaft arranged in parallel to the first input shaft,
• a dual clutch having a first clutch for transmitting a rotational drive power from a prime mover to the first input shaft and a second clutch for transmitting the rotational drive power to the second input shaft,
• a plurality of odd-number stage drive gears comprising gears for odd-number stages and fixedly provided on the first input shaft,
• a plurality of even-number stage drive gear comprising gears for even-number stages and fixedly provided on the second input shaft,
• a plurality of first driven gears provided on the first output shaft to be freely rotatable, including at least a lowest speed driven gear and meshing with some gears of the odd-number stage drive gears and the even-number stage drive gears,
• a plurality of second driven gears provided on the second output shaft to be freely rotatable, including at least a highest speed driven gear and meshing with remaining gears of the odd-number stage drive gears and the even-number stage drive gears,
• a reverse gear provided on the first output shaft to be freely rotatable and meshing with a 2nd speed driven gear of the plurality of second driven gears,
• a first output shaft side gearshift clutch for connecting a gear selected from the plurality of first driven gears and the reverse gear with the first output shaft not to be relatively rotatable, and
• a second output shaft side gearshift clutch for connecting a gear selected from the plurality of second driven gears with the second output shaft not to be relatively rotatable,
• wherein the 2nd speed driven gear comprises:
• a large-diameter gear meshing with a 2nd speed drive gear of the even-number stage fixed gears, and
• a small-diameter gear provided bodily with the large-diameter gear, being fewer in tooth number and smaller in diameter than the large-diameter gear and meshing with the reverse gear.