Automatic transmission

An automatic transmission, comprising:

• an input shaft that is drivingly coupled to a drive source;
• a reduction planetary gear that has a first sun gear, a first carrier, and a first ring gear, and that can output decelerated rotation decelerated from input rotation of the input shaft;
• a planetary gear set that has a second sun gear, a third sun gear, a second carrier supporting a short pinion meshing with the third sun gear and a stepped pinion having a small diameter portion meshing with the short pinion and a large diameter portion meshing with the second sun gear such that the short pinion and the stepped pinion are rotatable, a second ring gear meshing with the large diameter portion, and a third ring gear meshing with the small diameter portion;
• a first clutch capable of inputting the decelerated rotation of the reduction planetary gear to the third sun gear;
• a second clutch capable of inputting the input rotation of the input shaft to the third ring gear;
• a third clutch capable of inputting the decelerated rotation of the reduction planetary gear to the second sun gear;
• a fourth clutch capable of inputting the input rotation of the input shaft to the second carrier;
• a first brake capable of preventing the second sun gear from rotating;
• a second brake capable of preventing the second carrier from rotating;
• a third brake capable of preventing the third ring gear from rotating;
• and
• an output member drivingly coupled to the second ring gear, wherein
• the automatic transmission is configured to achieve at least ten forward speeds and one reverse speed.