Translation guide
A gearbox is a mechanical component that transmits power and changes speed/torque via gears. In Japanese, the most common term is ギアボックス, but other words exist depending on context.
The mechanical device containing gears, used in vehicles and machinery.
The most direct and widely understood loanword for 'gearbox'. Used in automotive and general mechanical contexts.
This car's gearbox is not working well.
A technical term meaning 'transmission' or 'speed change device'. Often used in engineering and formal contexts.
We need to review the design of the gearbox.
Often used interchangeably with 'gearbox' in automotive contexts, though technically 'transmission' includes the entire drivetrain. Common in car talk.
I changed the transmission to automatic.
Referring specifically to the housing or assembly containing gears, often in industrial machinery.
Literally 'gear box'. A more descriptive term, used in mechanical engineering but less common than ギアボックス.
The gears inside the gearbox are worn out.
An alternative spelling of ギアボックス, sometimes seen in older texts or specific brands.
This machine's gearbox is custom-made.
ギアボックス is the everyday loanword. 変速機 is the formal technical term. トランスミッション is common in automotive contexts but can imply the whole transmission system. For general use, stick with ギアボックス.
The gearbox broke down.
The transmission needs maintenance.
The gearbox needs oil.
He repaired the gearbox.