The input shaft has only one gear that engages with a gear on the secondary shaft. When it is running and the clutch is engaged, the gearbox is in "Neutral". No gears on the primary shaft are engaged with gears on the secondary shaft.
When shifting into first gear, the gear on the primary shaft is slowed down by a synchronization mechanism, and aligned with a gear on the secondary shaft.
The current gear is always disengaged before the next one is engaged. When the clutch is engaged, rotational energy is transferred from the transmission to the axle(s) by the drivetrain. By using progressively smaller ratios, the speed of the vehicle can be maintained or increased using less power from the engine.
When shifting into first gear, the gear on the primary shaft is slowed down by a synchronization mechanism, and aligned with a gear on the secondary shaft.
The current gear is always disengaged before the next one is engaged. When the clutch is engaged, rotational energy is transferred from the transmission to the axle(s) by the drivetrain. By using progressively smaller ratios, the speed of the vehicle can be maintained or increased using less power from the engine.