A crushable metal or composite structure mounted between the bumper beam and the main frame rails. It is engineered to deform predictably during low-speed impacts, absorbing kinetic energy to protect the chassis. In older mechanic slang, a crash box also refers to an unsynchronized manual transmission that requires double-clutching to avoid grinding gears.
Heard on the job
Cut the welds on the deformed crash box and prep the rail for the new replacement section.
Also heard as
- crush can
- impact absorber
Related terms
Bumper
A structure attached to the front and rear of a vehicle to absorb low-speed impacts.
Frame rail
One of the main longitudinal steel beams that form the foundation of a body-on-frame vehicle.
Manual transmission
A gearbox requiring the driver to manually select gear ratios using a shift lever and a clutch.