TRANSMISSION DEVICE

摘要

A fastening portion is formed from a rivet hole of a first side wall portion of a clutch drum, a rivet hole of a second side wall portion of a clutch drum, and a rivet that is inserted into the rivet hole and the rivet hole to hold together the first side wall portion and the second side wall portion. The fastening portion is provided between a first engagement side oil chamber enclosed by the clutch drum and a clutch piston, and a second engagement side oil chamber enclosed by the clutch drum and a clutch piston.