noun
Mechanical device that changes speed or torque, typically in vehicles or machinery.
この車はオートマチック変速機を搭載している。
This car is equipped with an automatic transmission.
変速機のオイルを交換する必要がある。
The transmission fluid needs to be changed.
Katakana loanword for 'gearbox', more specific to the housing containing gears; 変速機 can refer to the entire transmission system.
Compound of 変速 (hensoku, 'speed change') + 機 (ki, 'machine').