M6 | |
---|---|
Overview | |
Manufacturer | Chrysler Corporation |
Also called | Presto-Matic Tip-Toe Shift Gyro-Matic Fluid-Matic Fluidtorque Gyrotorque Fluid Drive |
Production | 1946–1953 |
Body and chassis | |
Class | 2-speed semi-automatic transmission (manual with overdrive and torque converter) |
Chronology | |
Predecessor | M4 Vacamatic |
Successor | PowerFlite |
The M6 Presto-Matic was a Chrysler Corporation semi-automatic transmission produced from 1946 to 1953. It was a special manual transmission with a fluid coupling. Although it had just two forward gears, an electric overdrive unit was attached and useful in either gear for a total of four forward speeds.
The driver would use the clutch pedal any time when selecting low, high, or reverse gear. Once underway, the accelerator could be eased and the car would engage the overdrive. With the Fluid Drive coupling, the car could be brought to a halt in gear without releasing the clutch and would creep like an automatic.
The Presto-Matic name was only used on Chrysler-brand cars. DeSoto called the transmission the Tip-Toe Shift, while Dodge used Gyro-Matic, Fluid-Matic, Fluidtorque, or Gyro-Torque. Chrysler and DeSoto sold the unit from 1946 to 1953, while Dodge did not introduce it until 1948. Plymouth introduced their Hy-Drive semi-automatic in 1953, but all were replaced by the PowerFlite hydraulic automatic in 1954.
Attached to the transmission was an “underdrive” with a reduction gear of 1.75/1. The shift lever was column-mounted and had three positions: Low (in the “2nd” position of a conventional 3-speed manual unit), High (in the “3rd” position), and Reverse (same as the 3-speed). The clutch had to be depressed every time the gear shift lever was moved. When the lever was put in Low, the car started in “underdrive” low; when the vehicle reached a minimum speed of 6 mph (9.7 km/h), the driver lifted his foot off the accelerator, the underdrive unit would kick out and the car would be in Low. Similarly, with the lever in High position, the car would start in underdrive high, and at any speed above 13 mph (21 km/h), the driver would lift his foot and the car would “shift” into direct drive.
This configuration had the effect of providing 4 gear ratios:
In order for the unit to work without gear clashing, it contained a freewheeling device (in Underdrive, Low and High), and the Owner's manual cautioned drivers not to use “1st or 3rd” gear when descending hills because there was no engine compression braking in those free-wheeling ranges. Generally, most drivers started an M6 car in High and accomplished the shift to direct drive somewhere between 13 and 25 MPH by releasing the accelerator pedal and waiting for the “clunk” that signaled the disengagement of the underdrive. An M6 car would automatically shift from High down to underdrive high when car speed dropped below approximately 11 MPH.
An automatic transmission is a multi-speed transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions.
Overdrive is the operation of an automobile cruising at sustained speed with reduced engine speed (rpm), leading to better fuel consumption, lower noise, and lower wear. The term is ambiguous. The most fundamental meaning is that of an overall gear ratio between engine and wheels, such that the car is over-geared, and cannot reach its potential top speed, i.e. the car could travel faster if it were in a lower gear, with the engine turning at higher RPM.
A manual transmission (MT), also known as manual gearbox, standard transmission, or stick shift, is a multi-speed motor vehicle transmission system where gear changes require the driver to manually select the gears by operating a gear stick and clutch.
A semi-automatic transmission is a multiple-speed transmission where part of its operation is automated, but the driver's input is still required to launch the vehicle from a standstill and to manually change gears. Semi-automatic transmissions were almost exclusively used in motorcycles and are based on conventional manual transmissions or sequential manual transmissions, but use an automatic clutch system. But some semi-automatic transmissions have also been based on standard hydraulic automatic transmissions with torque converters and planetary gearsets.
The modern usage of the automotive term manumatic denotes an automatic transmission that allows the driver to select a specific gear, typically using paddle-shifters, steering wheel-mounted push-buttons, or "+" and "-" controls on the gear selector.
Hydramatic is an automatic transmission developed by both General Motors' Cadillac and Oldsmobile divisions. Introduced in 1939 for the 1940 model year vehicles, the Hydramatic was the first mass-produced fully-automatic transmission developed for passenger automobile use.
TorqueFlite is the trademarked name of Chrysler Corporation's automatic transmissions, starting with the three-speed unit introduced late in the 1956 model year as a successor to Chrysler's two-speed PowerFlite. In the 1990s, the TorqueFlite name was dropped in favor of alphanumeric designations, although the latest Chrysler eight-speed automatic transmission has revived the name.
Dynaflow was the trademarked name for a type of automatic transmission developed and built by General Motors Buick Motor Division from late 1947 to mid-1963. The Dynaflow, which was introduced for the 1948 model year only as an option on Roadmaster models, received some severe early testing in the M18 Hellcat tank destroyer, which were built in Buick's Flint Assembly plant during World War II. It was also used in the 1951 Le Sabre concept car.
Ford-O-Matic was the first automatic transmission widely used by Ford Motor Company. It was designed by the Warner Gear division of Borg Warner Corporation and introduced in 1951 model year cars, and was called the Merc-O-Matic when installed in Mercury branded cars and Turbo-Drive when installed in Lincoln branded cars. In contrast to Detroit Gear Division's three band automatic originally designed for Studebaker which became superseded by this unit, a variation of Warner Gear's three-speed unit named Ford-O-Matic continued to evolve later into Cruise-O-Matic named transmissions in 1958 and finally the FMX named transmissions in 1968. This line continued in production until 1980, when the AOD was introduced. Like Ford, variations of this same Borg Warner design were used by other automobile manufacturers as well, such as AMC, International Harvester, Studebaker, Volvo and Jaguar, each of them having the necessary unique adaptations required for the individual applications.
The Powerglide is a two-speed automatic transmission designed by General Motors. It was available primarily on Chevrolet from January 1950 through 1973, although some Pontiac models also used this automatic transmission after the fire at the Hydra-Matic factory in 1953. Powerglides were used extensively on Pontiacs produced for the Canadian market with Chevrolet powertrains. They were also used with Nova engines in the DJ-5A Jeeps produced 1968-1970 by Kaiser-Jeep and widely used as delivery vehicles by the United States Post Office. When introduced on upper-level Chevrolet models in 1950, the Powerglide represented the first automatic transmission offered in a low-priced automobile; in contrast, Ford did not offer their automatic transmission until 1951, while Plymouth car buyers had to wait until 1954. The transmission was simple and very durable, which satisfied customers.
A direct-shift gearbox is an electronically controlled, dual-clutch, multiple-shaft, automatic gearbox, in either a transaxle or traditional transmission layout, with automated clutch operation, and with fully-automatic or semi-manual gear selection. The first dual-clutch transmissions were derived from Porsche in-house development for the Porsche 962 in the 1980s.
A preselector gearbox is a type of manual transmission mostly used on passenger cars and racing cars in the 1930s, in buses from 1940–1960 and in armoured vehicles from the 1930s to the 1970s. The defining characteristic of a preselector gearbox is that the gear shift lever allowed the driver to "pre-select" the next gear, usually with the transmission remaining in the current gear until the driver pressed the "gear change pedal" at the desired time.
A transmission control unit (TCU), also known as a transmission control module (TCM), or a gearbox control unit (GCU), is a type of automotive ECU that is used to control electronic automatic transmissions. Similar systems are used in conjunction with various semi-automatic transmissions, purely for clutch automation and actuation. A TCU in a modern automatic transmission generally uses sensors from the vehicle, as well as data provided by the engine control unit (ECU), to calculate how and when to change gears in the vehicle for optimum performance, fuel economy and shift quality.
The Hy-Drive was a Chrysler Corporation semi-automatic transmission introduced in 1953 in US-market Plymouths. It was a hybrid manual transmission equipped with a torque converter, like an automatic. Although Hy-Drive cars had a clutch pedal like a traditional manual transmission, it was only used to put the car in gear. Once underway, the driver could upshift and downshift using the gear shift without using the clutch or even lifting off the accelerator.
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. 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.
A gear stick, gear lever, gearshift or shifter, more formally known as a transmission lever, is a metal lever attached to the transmission of an automobile. The term gear stick mostly refers to the shift lever of a manual transmission, while in an automatic transmission, a similar lever is known as a gear selector. A gear stick will normally be used to change gear whilst depressing the clutch pedal with the left foot to disengage the engine from the drivetrain and wheels. Automatic transmission vehicles, including hydraulic automatic transmissions, automated manual and older semi-automatic transmissions, like VW Autostick, and those with continuously variable transmissions, do not require a physical clutch pedal.
The name Autostick has been used for a Volkswagen semi-automatic transmission, which is a vacuum-operated automatic clutch system, coupled with a conventional 3-speed manual transmission. The "AutoStick" system designed by Chrysler allows for manual selection of gears with a standard hydraulic automatic transmission, also known as a manumatic.
The 1941 M4 Vacamatic transmission by Chrysler was, historically, the first semi-automatic transmission which was marketed by a major manufacturer. It was an attempt to compete against rivals' hydraulic automatic transmissions, though it still had a clutch, primarily to change range. In normal driving, the clutch is not used. The transmission itself was a fully-synchronized manual transmission, with four forward gears, one reverse; where the shifting was done 'automatically' by either vacuum cylinders, or hydraulic cylinders. The main difference was the addition of a fluid coupling between engine and clutch, and the shifting mechanism.
Car controls are the components in automobiles and other powered road vehicles, such as trucks and buses, used for driving and parking.