Non-synchronized transmissions may use a clutch brake. The brake is a steel hub with two tangs, encased in a cover that has a facing material bonded to both sides.

The purpose of the clutch brake is to slow down or stop the transmission input shaft from rotating.

When the operator depresses the clutch pedal to the floorboard, beyond the normal clutch disengage position, the clutch release bearing comes in contact with the clutch brake and the transmission input shaft bearing cover.

Because the tangs on the brake hub are engaged in the transmission input shaft splines, the transmission is slowed down or stopped.

The driver can then shift from first to reverse or from reverse to first without clashing or putting undue strain on the gears.