During its early years, Rolls-Royce prided itself on making all the mechanical components for its cars; how else could it guarantee ‘the best car in the world’ if parts from others were fitted? But as motor carinterest in technical developments on the other side of the Atlantic, and saw some early Hydramatic transmission prototypes during the early 1930s. During the war, despite having more pressing concerns, RollsRoyce experimented with automatic gearboxes in existing models, and deemed the Hydramatic worthy of fitment. Rather than buy in the gearboxes, Robotham forged a deal during 1946 to manufacture up to 5000 per year under licence. The plan stalled somewhat when Robotham was shifted away from the passenger car division to Rolls-Royce's new diesel engine section, but in early 1952, Crewe finally started building the Hydramatic - not that it was officially called this, as the company made it clear that it should be referred to simply as ‘the automatic gearbox’ in marketing and by the press. It was initially only available for export machines, but became available for the home market in autumn 1953, for an extra £99 3s and 4d. Some examples were also sold to Armstrong Siddeley for its Sapphire 346 and to the British Motor Corporation for Vanden Plas Princesses. Although the advent of the Silver Shadow in 1965 saw the Hydramatic gradually phased out in favour of the GM400 threespeed self-shifter, it remained in service with Phantoms up until 1978.
