Configuration
The standard Fluid Drive configuration consisted of the fluid coupling and a manual transmission and clutch in tandem. If the Fluid Drive was mated to a manual transmission, the driver still needed to use the clutch to shift between any of the gears. The presence of Fluid Drive, however, prevented the driver stalling when taking off from a dead stop. The driver could also come to a stop in third gear without using the clutch and proceed without downshifting. It must be emphasized that Fluid Drive was not a transmission, only a fluid coupling between the engine and clutch.
Fluid Drive could also be mated to the semi-automatic transmission, which was not automatic in any way and should not be confused with Fluid Drive. With the semi-automatic transmissions, the driver shifted manually, selecting reverse or a low range and a high range. Each 'range' had two speeds. To shift between them, the driver accelerated then released pressure on the accelerator. In high range, this shift point was about 23 mph (37 kmh). The transmission shifted into high speed range, the driver then depressed the accelerator pedal, and continued accelerating. The solenoids on the transmission connected to the carburetor and ignition system and momentarily interrupted engine operation to allow trouble-free shifting.
The driver could down-shift for passing by fully depressing the accelerator. The clutch was needed to change between low and high range. The fluid drive system allowed the driver to stop at a light or in traffic and remain in gear without depressing the clutch. The driver could, if not concerned with fast acceleration, drive the car all day long in high range, stopping and starting, without ever having to touch the clutch pedal or gearshift lever unless faster acceleration or reversing was required. For this reason, DeSotos and Dodges were favored by city cab companies from the mid Forties to early Fifties.
The semi-automatic came under a variety of names - Vacamatic, Prestomatic, Fluidmatic (Chrysler), Simplimatic, Tip-Toe Hydraulic Shift (DeSoto) and Gyromatic (Dodge).
A Fluid Drive Dodge with Gyromatic was far cheaper than a Hydramatic-equipped Pontiac, and had the effect of making city taxi-driving far easier. In 1950, a Dodge Coronet, which had Fluid Drive standard, offered Gyromatic for $94.60, while Hydramatic was a $158.50 option on Pontiacs.
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