The company moved a number of times in the early years, and in 1938 settled in premises at Lythalls Lane, Coventry.
[1] Many of British Railways' first generation diesel multiple units and shunting locomotives had gearboxes made by Self-Changing Gears.
Gearboxes installed in locomotives built by the Vulcan Foundry for the Drewry Car Company were designated "Wilson-Drewry".
Buses on city work need to start and stop every minute or less, and the effort required with a manual gearbox was substantial.
In addition, for most of the period when these transmissions were dominant buses still had unassisted steering, and the overall effort needed without assistance was fatiguing.
From about 1935 to 1960, buses by AEC, Daimler, and sometimes Bristol, Guy and Leyland offered Preselector gearboxes, either as an option or as standard.