Fluid Drive
The topic of Fluid Drive is a topic of great relevance in today's society. This is an issue that affects a large number of people, and that arouses great interest and concern in the population. It is a topic that has been the subject of numerous studies, research and debates in recent years, demonstrating its importance and the need to address it appropriately. In this article, we will analyze Fluid Drive in depth, exploring its causes, consequences and possible solutions, with the aim of offering a broad and complete vision of this very relevant topic.
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| Automotive transmissions |
|---|
| Manual |
| Automatic / Semi-automatic |
Fluid Drive is the trademarked name that Chrysler Corporation assigned to a transmission driveline combination which replaced the flywheel with a hydraulic coupling and performed the same function as a modern torque converter, only without torque multiplication.[1] A conventional clutch and three- or four-speed manual transmission was installed behind the fluid coupling. Fluid drive was used in many military vehicles produced for the US Armed Forces during the Second World War. It was offered for civilian use from 1939 through 1953 in Chryslers, 1940 through 1953 in DeSotos, and from 1941 through 1954 in Dodge models; a semi-automatic system was optional from Chrysler and DeSoto from 1941, and for Dodge from 1949.
History
The fluid coupling and torque converter was invented by the German engineer Hermann Föttinger in the early 1900s.[2] For non-marine applications he licensed the development of the fluid coupling to the British engineer Harold Sinclair and his Fluidrive Engineering Co Ltd (now part of Voith AG). Following the development of the fluid coupling, Sinclair in turn licensed the fluid coupling, now also known as "Fluidrive Coupling" to many companies including the Chrysler Corporation.
Configuration
The standard Fluid Drive configuration consisted of the fluid coupling and a manual transmission and clutch in tandem.[3] 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 stop. The driver could also come to a stop in any gear without using the clutch and could then proceed without shifting or using the clutch.[3] Acceleration from a stop would be much slower in high gear than it was in first. Fluid Drive was not the transmission itself, but a fluid coupling between the engine and clutch.
Fluid Drive could also be mated to a semi-automatic transmission. With the semi-automatic transmission, the driver selected reverse, low range, or high range. Each range had two speeds; to shift between them, the driver accelerated then released pressure on the accelerator.[1] In high range, this shift point was about 23 mph (37 km/h). Once the transmission shifted into high gear, the driver again depressed the accelerator pedal, and continued accelerating. To downshift for passing, the driver would fully depress the accelerator. Solenoids on the transmission connected to the carburetor and ignition system momentarily interrupted engine operation to allow trouble-free shifting.
The clutch was needed to change between low and high range or to reverse, but 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, keep the car in high range, stopping and starting without ever having to use 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-1940s to early 1950s.
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 less expensive 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 ($956.22 in 2017 dollars), while Hydramatic was a $158.50 option ($1,602.12) on Pontiacs.
M4 and M6 transmissions
The fluid drive fluid coupling was also used in conjunction with Chrysler's M4 Vacamatic and M6 Presto-Matic semi-automatic transmissions.
See also
References
- ^ a b Gold, Aaron (December 29, 2020). "How Chrysler Was Once Detroit's Technological Leader". Motor Trend. Retrieved November 29, 2025.
- ^ Nunney, Malcolm James (2007). Light and Heavy Vehicle Technology. Butterworth-Heinemann. p. 317. ISBN 978-0-7506-8037-0.
- ^ a b "Video: An Introduction to Chrysler Fluid Drive". Mac's Motor City Garage. October 24, 2017. Retrieved November 29, 2025.
