Fluidrive

Fluidrive was a system used by Chrysler in which a hydraulic fluid coupling was installed between the engine and the gearbox. The fluid coupling replaced the conventional mechanical clutch as the connection between the engine and transmission.

One of the advantages of Fluidrive was that the car could come to a stop and move away again without the engine stalling when the clutch pedal was not operated. However, in the original Fluidrive system, a conventional manual gearbox was still used, meaning that the driver still had to operate the clutch when changing gears.

Chrysler later combined Fluidrive with a semi-automatic transmission. In this configuration, the driver could change gears with considerably less use of the clutch pedal. This is why Fluidrive is sometimes described as a “clutchless gear change” system. Technically, however, this description does not apply to every Fluidrive configuration, as the exact operation depended on the transmission fitted to the car.

Fluidrive is particularly interesting when working on American classic cars from the 1940s and 1950s. When maintaining or restoring a car equipped with Fluidrive, it is important to establish exactly which version of the system is fitted, as the operation and adjustment can differ between Fluidrive systems combined with a manual gearbox and those using a semi-automatic transmission.