The term gearshift is really an anachronism, left over from a time when
low-cost farm tractor motors were directly coupled to the drive wheels
using variable gear sets. Because the tractor loads were high and the
engines were weak, power dissipation was unnecessary. However, it was
necessary for the framers to physically exchange gear sets to match the
tractor speed to varying terrain or applications. This was done by
stopping the tractor and unscrewing one gear set in order to replace it
with another, known as 'shifting gears'. In recent times only one
manufacturer has attempted to build a passenger vehicle with a true gear
shift transmission. In a vehicle with a gearshift transmission requires a torque free state to shift gears. The riding comfort is improved by a method of shifting gears where a gear shift is preceded by reducing the vehicle acceleration from an existing level to a first acceleration level, maintaining the vehicle acceleration at a reduced level for a predetermined time interval.
The gearshift transmission is said to put up to 20% more horsepower to the rear wheels. The engine is smooth, powerful, quick starting and fairly quiet.