During the 1920s and 1930s, several French luxury car manufacturers used a three- or four-speed preselector gearbox, manufactured by Cotal. One of the most up-and-coming brands, Peugeot, established a good business relationship with the transmission manufacturer, beginning to build a beautiful technical tradition.
A unique aspect of the Cotal gearbox was the use of electromagnetic clutches (instead of band brakes) to engage the gears. The Cotal gearbox basically consisted of three basic elements: the actual gearbox; the gear selector (lever or “mustard”) positioned behind the steering wheel; a second selector (direction, forward or reverse) made with lever or knob and placed on the dashboard or under it. The gear selector was connected by means of electrical wiring to the gearbox and moved inside four rotating electromagnets which in turn contained several trains of gears. These, according to the way in which they were combined, created the four different levels of reduction, with the fourth ratio usually over-multiplied to reduce consumption. This was possible for both forward and reverse. In the latter case, simply by acting on the selector located on the dashboard or under the dashboard.
Peugeot chose this gearbox for its flagship 402 during the 1930s. Initially intended for a privileged few, in the brand’s programs, it should then have been progressively introduced on lower-class cars. This ambitious program was stopped due to the Second World War. Without the conflict, perhaps it would have been more successful: the Cotal was very quiet and reliable, as all couplings always took place on planes perpendicular to the drive axle, thus reducing wear.
According to tests of the time, carried out on the road and on the circuit, the 402s with Cotal gearbox ensured a fuel saving of around 25% compared to those equipped with a classic mechanical gearbox. There would be no proof using the current more precise methods to establish this record with certainty, of course, but at the time it was considered a very interesting statistic.