An automatic transmission is a multi-speed transmission used in motor vehicles that does not require any driver input to change gears under normal driving conditions. It typically includes a transmission, axle, and differential in one integrated assembly, thus technically becoming a transaxle.
A transmission is a machine in a power transmission system, which provides controlled application of power. Often the term 5-speed transmission refers simply to the gearbox, that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device.
A manual transmission 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.
Semi-automatic transmission denotes a multi-speed motor vehicle transmission where part of its operation is automated, but the driver's input is still required to start from a standstill and to manually change gears. Most semi-automatic transmissions used in cars and motorcycles are based on conventional manual transmissions or a sequential manual transmission, but use an automatic clutch system. However, some semi-automatic transmissions have also been based on standard hydraulic automatic transmissions, with a fluid coupling or torque converter.
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.
PowerFlite is a two-speed automatic transmission engineered and produced by the Chrysler Corporation and used in their passenger cars from 1954 to 1961. Production began in late 1953; despite the launch of Chrysler's three-speed TorqueFlite automatic in 1956, the simple and durable PowerFlite remained available on Plymouths and Dodges through the 1961 model year, after which it was discontinued.
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, Michigan assembly plant during World War II. It was also used in the 1951 Le Sabre concept car.
Turbo-Hydramatic or Turbo Hydra-Matic is the registered tradename for a family of automatic transmissions developed and produced by General Motors. These transmissions mate a three-element turbine torque converter to a Simpson planetary geartrain, providing three forward speeds plus reverse.
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.
7G-Tronic is Mercedes-Benz's trademark name for its seven-speed automatic transmission, starting off with the W7A 700 and W7A 400 as core models.
Roto Hydramatic was an automatic transmission built by General Motors and used on some Oldsmobile, Pontiac and Holden models from 1961–1965. It was based on the earlier, four-speed Hydramatic, but was more compact, providing only three forward speeds plus a small 8" fluid coupling with a stator inside of the fluid coupling. Oldsmobile, one of the users of this transmission, called the fluid couplings stator the "Accel-A-Rotor." The lightweight, aluminum-cased transmission was sometimes nicknamed the "Slim Jim." HydraMatic Division calls the Roto a four range, three gear HydraMatic. It counts the stator multiplication at 3.50:1 as a first gear, and when road speed and the two coupling halves speed match, it counts the same gear with fluid now passing straight through the stator as 2nd gear at 2.93 to one. Second gear has a ratio of 1.56 and because the fluid coupling is drained for this gear ratio making the front clutch apply makes this a rare automatic that is in FULL mechanical lock-up in second gear. Fourth range the coupling fills releasing the front clutch makes a ratio of 1 to 1. This transmission, like single and dual range, and dual coupling hydramatics also have the feature of split torque in the transmission whereby in fourth or high gear only 40-to 50% depending on transmission, 40% in Roto's case, but because of the design the coupling is only required to carry 40% of the engine torque. The rest is (60%) is in full mechanical connection making these hydramatics the most efficient automatic until the wide spread use of the lock-up torque converter.
The Ultradrive is an automatic transmission manufactured by Chrysler beginning in the 1989 model year.
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 various semi-automatic transmissions, purely for clutch automation. 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.
The M6 Presto-Matic was a Chrysler Corporation semi-automatic transmission produced from 1946–1953. 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 name Autostick has been used for a Volkswagen semi-automatic transmission, which was 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. Similar systems have been offered and are marketed by other automakers. The Autostick systems used by Volkswagen and Chrysler are largely unrelated, and are not mechanically similar in their operation, and do not share any similarities with their internal design and build.
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.
Mopar branded automatic transmission fluids (ATF) have been available for use in Chrysler fully automatic transmissions since 1953. Other Mopar branded fluids for their Fluid Drive semi-automatic transmissions were available as early as 1938. Chrysler used General Motors (GM) automatic transmission fluid specifications from 1952 through 1966 and marketed them under the Mopar brand name. In 1966, Chrysler began releasing their own automatic transmission fluid specifications. Chrysler licenses their ATF specifications to companies which manufacture the fluid and sell it under their own brand names. Not all Chrysler fluids are licensed for reselling under another brand name. All licensed Chrysler fluids must have a license number on the container. If no license number is found, the fluid may not be Chrysler approved and the fluid cannot be guaranteed to meet Chrysler specifications.
