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98-674: 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 In contrast to Detroit Gear Division's three band automatic originally designed for Studebaker which became superseded by this unit,

196-429: A clutchless manual , is a type of multi-speed automobile transmission system that is closely based on the mechanical design of a conventional manual transmission , and automates either the clutch system, the gear shifting, or both simultaneously, requiring partial, or no driver input or involvement. Earlier versions of these transmissions that are semi-automatic in operation, such as Autostick , control only

294-419: A 195 hp V8 engine. The transmission was controlled by a dial-button panel with four regimes: Зх, Н, Д, Т corresponding to Reverse, Neutral, Drive and "Braking". In Drive the car was would start in first and sequentially shift to third and back. In "Braking" (i.e. engine braking), third gear would be locked out, and the first gear would be engaged by the rear band immobilizing the planetary carrier, rather than

392-463: A Cruis-O-Matic based transmission. Automatic transmission The most common type of automatic transmission is the hydraulic automatic , which uses a planetary (epicyclic) gearset , hydraulic controls , and a torque converter . Other types of automatic transmissions include continuously variable transmissions (CVT), automated manual transmissions (AMT), and dual-clutch transmissions (DCT). The 1904 Sturtevant "horseless carriage gearbox"

490-529: A band on the rear unit internal gear drum provided reverse. This transmission was offered on Ford models Falcon, Fairlane, and Galaxie, Mercury models Comet, and Meteor and Edsel cars with differences in the torque converter, valve bodies and clutch plates to accommodate differing engine torques. In 1966, Ford introduced the C6 automatic, which left them with three heavy-duty automatic transmissions and crowded conditions at Livonia Transmission plant. Ford decided to combine

588-508: A constant angular velocity while the vehicle moves at varying speeds. CVTs are used in cars , tractors , UTVs , motor scooters , snowmobiles , and earthmoving equipment . The most common type of CVT uses two pulleys connected by a belt or chain , however, several other designs have also been used. A dual-clutch transmission (DCT, sometimes referred to as a twin-clutch transmission , or double-clutch transmission ) uses two separate clutches for odd and even gear sets . The design

686-415: A designated transmission control unit (TCU) for the clutch and shifting, plus steering wheel-mounted paddle shifters, if the driver wanted to change gear manually. Modern fully automatic AMTs, such as Selespeed and Easytronic , have now been largely superseded and replaced by the increasingly widespread dual-clutch transmission design. Ravigneaux planetary gearset The Ravigneaux gearset

784-479: A form of manual transmission which removed the reliance on the driver's skill to achieve smooth gear shifts. The first automatic transmission using hydraulic fluid was developed in 1932 by two Brazilian engineers, José Braz Araripe and Fernando Lehly Lemos. The evolution towards mass-produced automatic transmissions continued with the 1933–1935 REO Motor Car Company Self-Shifter semi-automatic transmission, which automatically shifted between two forward gears in

882-600: A full licence (the GAZ factory was designed by the Ford Motor Company , later the Lada factory would be built by Fiat etc.) or make an indigenous copy by reverse engineering. In the 1950s, as the GAZ plant was preparing to launch its new generation of cars, that comprised the mid-size GAZ-21 Volga sedan and the full-size GAZ-13 Chaika limousine, it was specified that both vehicles feature

980-402: A large sun and a small sun, and a single planet carrier, holding two sets of planetary gears, inner planets and outer planets. The carrier is one sub-assembly but has two radii to couple with the inner and outer planets, respectively. The two sets of planet gears rotate independently of the carrier but co-rotate with a fixed gear ratio with respect to each other. The inner planets couple with

1078-413: A manual transmission. The 1904 Sturtevant "horseless carriage gearbox" is often considered to be the first automatic transmission for motor vehicles. At higher engine speeds, high gear was engaged. As the vehicle slowed down and engine speed decreased, the gearbox would shift back to low. However, the transmission was prone to sudden failure, due to the transmission being unable to withstand forces from

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1176-442: A more Spartan trimmed taxi version featured the three-speed manual. However, most of these cars were given as prizes to workers of distant regions for excellent results, instead of being kept in large cities, where they would be more practical. The "lucky" customers had great difficulty in obtaining adequate spare parts, qualified service and most of all, transmission fluid. As a result, many chose to simply convert their transmission to

1274-462: A new type of automatic transmission to emphasize fuel economy and driveability. The new transmission was built around the Ravigneaux planetary of the "X" transmissions. Where many transmissions had a fourth gear added as an afterthought, Ford's new transmission was designed with a fourth gear already integrated into the gearset. Because it was based on the X transmissions, its gear ratios from 1-3 were

1372-456: A patent was approved in the United States describing the operation of a transmission where the manual shifting of gears and manual operation of a clutch was eliminated. This patent was submitted by Henry R. Hoffman from Chicago and was titled: Automatic Gear Shift and Speed Control . The patent described the workings of such a transmission as "...having a series of clutches disposed intermediate

1470-640: A result of rising gas prices. The transmission was introduced when Ford downsized its full size line for 1979. Initially called XT-LOD (Extension Lock-Up Overdrive), its name was changed when revisited in 1974 to FIOD (Ford Integrated Overdrive) and then to its final name in 1979, the Ford AOD transmission . Despite the Cold War , the Soviet Union , in developing its automotive industry, would often base its products on western technology, from whom it would either purchase

1568-445: A separate transmission control unit . This allows for more precise control of shift points, shift quality, lower shift times and manual control. The first five-speed automatic was the ZF 5HP18 transmission , debuting in 1991 on various BMW models. The first six-speed automatic was the ZF 6HP26 transmission , which debuted in the 2002 BMW 7 Series (E65) . The first seven-speed automatic was

1666-409: A single planet carrier. It has two sun gears, two ring gears, and two sets of planet gears on a single carrier. Using a single carrier makes the Ravigneaux smaller, lighter, and less expensive to make, because the carrier is usually the largest and most expensive part of a planetary gearset. The original patent application proposed that electromagnetic clutches be used in the transmission. The year of

1764-422: A stuck car back and forth. The original Ford-O-Matic, while capable of three forward speeds, started out in second and shifted to third, with first only being used when selecting L on the gear shift column. However, if floored from a standing start, it would immediately shift from second to low then shift back to second and then third as the vehicle accelerated. The Ford-O-Matic was manufactured from 1951 until it

1862-553: 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

1960-505: Is a double planetary gear set, invented by Pol Ravigneaux , who filed a patent application on July 28, 1949, in Neuilly-sur-Seine France. This planetary gear set, commonly used in automatic transmissions , is constructed from two gear pairs, ring–planet and planet–planet. The gearset provides four forward gear ratios and reverse by braking or restraining various elements of the mechanism. The Ravigneaux set has two sun gears,

2058-465: Is a ring gear, also called an annulus, having internal teeth fitting around the carrier. Input power is applied to one or both sun gears, and output power is taken from the ring gear, which turns the drive shaft. The FMX transmission is controlled through two clutches called the forward and rear clutches, and two band brakes , called the forward and rear bands. The clutches and bands are operated by hydraulic pressure. In this case, forward means closest to

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2156-577: Is attributed to the increasing number of electric and hybrid cars, and the ease of integrating it with safety systems such as Autonomous Emergency Braking . The efficiency, power output as a percentage of input, of conventional automatic transmissions ranges from 86 to 94%. Manual transmissions are more fuel efficient than all but the newest automatic transmissions due to their inherently low parasitic losses, typically of about 4%, in addition to being cheaper to make, lighter, better performing, and of simpler mechanical design. However, manual transmissions have

2254-521: Is connected to the engine via a torque converter (or a fluid coupling prior to the 1960s), instead of the friction clutch used by most manual transmissions . A hydraulic automatic transmission uses planetary gearsets instead of the manual transmission's design of gears lined up along input, output and intermediate shafts. To change gears, the hydraulic automatic uses a combination of internal clutches, friction bands or brake packs. These devices are used to lock certain gears, thus setting which gear ratio

2352-404: Is difficult to count the total number of transmissions built (including replacements). What is known that 3189 GAZ-13 Chaikas, 1120 GAZ-14 Chaikas, 608 GAZ-23 Chasers were built, in addition to the ~700 original GAZ-21 Volgas. Anywhere between 2 and 2.5 thousand GAZ-24-24, 24-34 and 31013 Chasers can be added. Thus approximately 8000 vehicles were manufactured by the plant from 1958 to 1996 featuring

2450-493: Is held fixed, while another component is input, and the remaining component is used for output. By choosing a set of components for held, input, and output, the planetary gear will increase or decrease speed and change direction. The Ravigneaux improves upon earlier planetary automobile transmissions, such as the Simpson , which has two complete planetary gearsets. As originally invented, the Ravigneaux puts two planetary gear trains on

2548-404: Is in use at a given time. A sprag clutch (a ratchet-like device which can freewheel and transmits torque in only one direction) is often used for routine gear shifts. The advantage of a sprag clutch is that it eliminates the sensitivity of timing a simultaneous clutch release/apply on two planetary gearsets, simply "taking up" the drivetrain load when actuated, and releasing automatically when

2646-449: Is integrated into the engine control unit (ECU). Modern designs have replaced the centrifugal governor with an electronic speed sensor that is used as an input to the TCU or ECU. Modern transmissions also factor in the amount of load on an engine at any given time, which is determined from either the throttle position or the amount of intake manifold vacuum. The multitude of parts, along with

2744-400: Is like a simple planetary gear set, except that each planet gear is replaced by a set of three gears, all on the same carrier. All three gears in a set are seen inside the carrier in the left photo. The gear on the right side of this photo is in slightly farther toward the center of the carrier than the gear it meshes with on the left. The left and right gears turn in the opposite direction. Only

2842-454: Is not possible to push start a vehicle equipped with an automatic transmission with no rear pump (aside from several automatics built prior to 1970, which also included a rear pump for towing and push-starting purposes). The pressure of the ATF is regulated by a governor connected to the output shaft, which varies the pressure depending on the vehicle speed. The valve body inside the transmission

2940-554: Is often considered to be the first true automatic transmission. The first mass-produced automatic transmission is the General Motors Hydramatic four-speed hydraulic automatic, which was introduced in 1939. Automatic transmissions are also found in some heavy commercial vehicles, particularly those which are subject to intense stop/start operation such as buses and waste collection vehicles . Vehicles with internal combustion engines, unlike electric vehicles, require

3038-505: Is often similar to two separate manual transmissions with their respective clutches contained within one housing, and working as one unit. In most car and truck applications, the DCT functions as an automatic transmission, requiring no driver input to change gears. The first DCT to reach production was the Easidrive automatic transmission introduced on the 1961 Hillman Minx mid-size car. This

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3136-450: Is pressurized by a pump and then directed to the appropriate bands/clutches to obtain the required gear ratio. The ATF provides lubrication, corrosion prevention, and a hydraulic medium to transmit the power required to operate the transmission. Made from petroleum with various refinements and additives, ATF is one of the few parts of the automatic transmission that needs routine service as the vehicle ages. The main pump which pressurises

3234-403: Is responsible for directing hydraulic pressure to the appropriate bands and clutches. It receives pressurized fluid from the main pump and consists of several spring-loaded valves, check balls, and servo pistons. In older automatic transmissions, the valves use the pump pressure and the pressure from a centrifugal governor on the output side (as well as other inputs, such as throttle position or

3332-615: The Mercedes-Benz 7G-Tronic transmission , which debuted a year later. In 2007, the first eight-speed transmission to reach production was the Toyota AA80E transmission . The first nine-speed and ten-speed transmissions were the 2013 ZF 9HP transmission and 2017 Toyota Direct Shift-10A (used in the Lexus LC ) respectively. The gear selector is the input by which the driver selects the operating mode of an automatic transmission. Traditionally

3430-475: The clutch system automatically — and use different forms of actuation (usually via an actuator or servo ) to automate the clutch, but still require the driver's input and full control to manually actuate gear changes by hand. Modern versions of these systems that are fully automatic in operation, such as Selespeed and Easytronic , require no driver input over gear changes or clutch operation. Semi-automatic versions require only partial driver input (i.e.,

3528-618: The "Forward" mode (or between two shorter gear ratios in the "Emergency low" mode). Driver involvement was still required during normal driving, since standing starts required the driver to use the clutch pedal. This was followed in 1937 by the Oldsmobile Automatic Safety Transmission . Similar in operation to the REO Self-Shifter , the Automatic Safety Transmission shifted automatically between

3626-424: The 1980s, automatic transmissions with four gear ratios became increasingly common, and many were equipped with lock-up torque convertors in order to improve fuel economy. Electronics began to be more commonly used to control the transmission, replacing mechanical control methods such as spring-loaded valves in the valve body. Most systems use solenoids which are controlled by either the engine control unit , or

3724-406: The 1990s, systems to manually request a specific gear or an upshift/downshift have become more common. These manumatic transmissions offer the driver greater control over the gear selection that the traditional modes to restrict the transmission to the lower gears. Use of the manumatic functions are typically achieved either via paddles located beside the steering column, or "+" and "-" controls on

3822-425: The ATF is typically a gear pump mounted between the torque converter and the planetary gear set. The input for the main pump is connected to the torque converter housing, which in turn is bolted to the engine's flexplate, so the pump provides pressure whenever the engine is running. A disadvantage of this arrangement is that there is no oil pressure to operate the transmission when the engine is not running, therefore it

3920-529: The Corvair. Most cars use a "P–R–N–D–L" layout for the gear selector, which consists of the following positions: Some automatic transmissions, especially by General Motors from 1940 to 1964, used a layout with reverse as the bottom position (e.g. N–D–L–R or P–N–D–L–R). Many transmissions also include positions to restrict the gear selection to the lower gears and engages the engine brake . These positions are often labelled "L" (low gear), "S" (second gear) or

4018-530: The DG transmission from its line-up. For 1957, Mercury offered mechanically activated pushbutton transmission controls in response to the Chrysler TorqueFlite pushbutton controls introduced in 1956. The Mercury control buttons initially offered five buttons and was called "Keyboard Control", with a long button on top labeled "Drive" with four smaller buttons below labeled "Brake", "Neutral Start" which would allow

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4116-610: The Hydra-Matic included a wide spread of ratios (allowing both good acceleration in first gear and cruising at low engine speed in top gear) and the fluid coupling handling only a portion of the engine's torque in the top two gears (increasing fuel economy in those gears, similar to a lock-up torque converter). Use of the Hydra-Matic spread to other General Motors brands and then to other manufacturers starting 1948 including Hudson , Lincoln , Kaiser , Nash , Holden (Australia), as well as Rolls-Royce and Bentley licensing production in

4214-494: The S1 set are pairwise coupled to S2 gears. The output can be coupled to either one of the ring gears, with R1 being used in all forward speeds and B in the reverse speed. The input always drives M1. In all forward speeds torque must be transferred between planet gears S1 and S2, since only S1 planets engage the input M1 and only S2 planets engage the output R1. In reverse gear the Ravigneaux behaves like an ordinary planetary system, with

4312-563: The UK and providing the transmission to Jensen Motors , Armstrong Siddeley and other UK manufacturers. During World War II, the Hydra-Matic was used in some military vehicles. The first automatic transmission to use a torque converter (instead of a fluid coupling) was the Buick Dynaflow , which was introduced for the 1948 model year. In normal driving, the Dynaflow used only the top gear, relying on

4410-711: The United States had automatic transmissions. Automatic transmissions have been standard in large cars since at least 1974. By 2020 only 2.4% of new cars had manual transmissions. Historically, automatic transmissions were less efficient, but lower fuel prices in the US made this less of a problem than in Europe. In the United Kingdom, a majority of new cars have had automatic transmissions since 2020. Several manufacturers including Mercedes and Volvo no longer sell cars with manual transmissions. The growing prevalence of automatic transmissions

4508-429: The abrupt gear changes. The adoption of planetary gearsets was a significant advance towards the modern automatic transmission. One of the first transmissions to use this design was the manual transmission fitted to the 1901–1904 Wilson-Pilcher automobile. This transmission was built in the United Kingdom and used two epicyclic gears to provide four gear ratios. A foot clutch was used for standing starts, gear selection

4606-455: The automatic transmission. Having evaluated many models, Borg-Warner's Ford-O-Matic and Cruise-O-Matic were selected. Despite very closely resembling the American transmissions, GAZ's copies did have distinctive differences. First of all – their components were adopted to the metric units. Their gear ratios – to the car's engines. Both cars' handbrake actuated a central drum between the housing and

4704-515: The best attributes of the MX and FX transmissions and ended up with an improved version of the "X" called FMX. This transmission used the stronger MX-type rotating parts in the smaller FX style case. This cut down on both weight and the number of transmission components Ford needed to make. This transmission was manufactured at the Fairfax Transmission Plant, freeing up capacity at Livonia for

4802-684: The car got a major facelift and internal modernisation with engine and chassis elements from the GAZ-3102 Volga, resulting in the GAZ-24-10 model. The Chaser became GAZ-24-34 and was produced until 1993. In 1977 GAZ launched its successor to the GAZ-13, the GAZ-14 Chaika . The new limousine had a more powerful engine, 220 hp, and its transmission was revised. Like for the GAZ-24, the central transmission brake

4900-580: The car was produced in small scale all the way until 1981. In 1963, GAZ introduced the third Soviet type of a KGB Q-car , the GAZ-23, by transplanting the large V8 engine and the powertrain of the Chaika into the unibody Volga. This car was used as a motorcade escort by the KGB's ninth directive (responsible for personal security of the party leadership) as well as surveillance teams of the 7th directorate. In 1970 GAZ-21 Volga

4998-594: The common three speed manual (that was a common universal model used in the GAZ-69 jeep and Volga's predecessor, the GAZ-M20 Pobeda ). Although the option was formally discontinued in 1964, most of the 700 cars were produced in the 1958 MY. As of 2017, only six such survivors were known. Chaikas, on the other hand, were available only with the transmission, and in 1962 it received a slight upgrade in number of clutch packs and piston shapes. Never available for private ownership,

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5096-401: The complex design of the valve body, originally made hydraulic automatic transmissions much more expensive and time-consuming to build and repair than manual transmissions; however mass-production and developments over time have reduced this cost gap. To provide coupling and decoupling of the engine, a modern automatic transmission uses a torque converter instead of the friction clutch used in

5194-456: The design before Ford could use it. Since the DG was available in Studebaker cars in mid-1950, this meant that Ford would have to wait until mid-1951 to introduce an automatic. The wait was unacceptable, so Ford went a different direction. Ford Engineering Vice President Harold Youngren, recently hired away from Borg-Warner, recommended that Ford license and build a transmission using a design he

5292-403: The disadvantage of requiring the driver to operate the clutch and change the gear whenever required. Fuel economy of course worsens with lower efficiency. Real-world tests reported in 2022 found that in typical driving manual transmissions achieved 2 to 5% better fuel economy than automatics, increasing to 20% with an expert driver. Some laboratory tests show automatics in a better light due to

5390-511: The drive shaft, instead of the rear wheels. Thus a parking pawl was deemed redundant. Volga's transmission, based on the Ford-O-Matic, required additional adaptation to the air-cooled torque converter, as it was driven by a 65 hp 4 cylinder engine. Controlled by a steering column mounted lever, it had four regimes: Зх-Н-Д-П (R-N-D-L). In Drive the car would start in second and automatically shift to third depending on throttle position (the valve

5488-446: The driver locking out the higher gears) to control which ratio is selected. As the vehicle and engine change speed, the difference between the pressures changes, causing different sets of valves to open and close. In more recent automatic transmissions, the valves are controlled by solenoids . These solenoids are computer-controlled, with the gear selection decided by a dedicated transmission control unit (TCU) or sometimes this function

5586-402: The driver must change gears manually), while fully automatic versions require no manual driver input, whatsoever ( TCU or ECU operates both the clutch system and gear shifts automatically). Modern automated manual transmissions (AMT) have their roots and origins in older clutchless manual transmissions that began to appear on mass-production automobiles in the early 1930s and 1940s, prior to

5684-411: The engine shaft and the differential shaft and in which the clutches are arranged to selectively engage and drive the differential shaft dependent upon the speed at which the differential shaft rotates". However, it would be over a decade later until automatic transmissions were produced in significant quantities. In the meantime, several European and British manufacturers would use preselector gearboxes ,

5782-494: The engine to operate in a narrow range of rates of rotation, requiring a gearbox, operated manually or automatically, to drive the wheels over a wide range of speeds. Globally, 43% of new cars produced in 2015 were manual transmissions, falling to 37% by 2020. Automatic transmissions have long been prevalent in the United States, but only started to become common in Europe much later. In Europe in 1997, only 10–12% of cars had automatic transmissions. In 1957 over 80% of new cars in

5880-446: The engine to start with the ignition key, "Hill Control" and "Reverse" with later versions separating the "Drive" button to "Performance" and "Cruising" for 1958 and relabeled as "Multi-Drive Keyboard Control". A separate push/pull lever was included below the control buttons labeled "Park" which would lock out the control buttons until the Park button was pulled to release it. The control panel

5978-427: The engine. When applied, a clutch connects a rotational component to the engine, causing the component to turn, and a band holds the component, preventing it from turning. The forward clutch controls power to the primary sun gear. The rear clutch controls power to the secondary sun gear. Confusingly, the band that holds the rear clutch is called the front band. The rear band holds the planet carrier. A Ravigneaux gearset

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6076-583: The first mass-produced automatic transmission following its introduction in 1939 (1940 model year). Available as an option in cars such as the Oldsmobile Series 60 and Cadillac Sixty Special , the Hydra-Matic combined a fluid coupling with three hydraulically controlled planetary gearsets to produce four forward speeds plus reverse. The transmission was sensitive to engine throttle position and road speed, producing fully automatic up- and down-shifting that varied according to operating conditions. Features of

6174-489: The gap between those gears, and one arm carrying the planets. Usually, the smaller diameter concentric gear has external teeth and is called a sun gear, and the larger concentric gear has internal teeth and is called a ring gear. The carrying arm is usually called the planet carrier. Planet gears are usually not directly coupled, leaving three components that are directly coupled: This provides for two inputs and one output. Usually, in an automatic transmission, one component

6272-433: The gear selector is located between the two front seats or on the steering column, however electronic rotary dials and push-buttons have also been occasionally used since the 1980s, as well as push buttons having been used in the 1950s and 1960s by Rambler (automobile) , Edsel , and most famously, by Chrysler . A few automobiles employed a lever on the instrument panel, such as the 1955 Chrysler Corporation cars, and notably,

6370-401: The gear selector. Some cars offer drivers both methods to request a manual gear selection. A continuously variable transmission (CVT) can change seamlessly through a continuous (infinite) range of gear ratios, compared with other automatic transmissions that provide a limited number of gear ratios in fixed steps. The flexibility of a CVT with suitable control may allow the engine to operate at

6468-406: The introduction of hydraulic automatic transmissions. These systems were designed to reduce the amount of clutch or gear shifter usage required by the driver. These devices were intended to reduce the difficulty of operating conventional unsynchronised manual transmissions ("crash gearboxes") that were commonly used at the time, especially in stop-start driving. An early example of this transmission

6566-549: The necessary unique adaptations required for the individual applications. In 1948, Ford realized it was late in introducing a fully automatic transmission to its automobile lineup. Ford initially approached Studebaker to purchase rights to use the DG-series automatic developed by the Detroit Gear division of Borg-Warner. The Studebaker board of directors was agreeable, but stipulated that Studebaker would have one year exclusive use of

6664-715: The new C6. The FMX was manufactured from 1968 to 1979, when the Fairfax Transmission plant was closed. Although the FMX was phased out in the United States in 1979 in favor of Ford's then-revolutionary Automatic OverDrive (AOD) transmission , the FMX was sold for another four years for use in V8 Ford Falcons built in Australia. The FMX ceased production when Ford Australia phased out the V8 engine in 1983. In 1962, Ford began working on

6762-539: The new three-speed transmissions were introduced. Production continued until it was replaced by the C4 in 1964 in smaller Ford and Mercury vehicles. The Ford-O-Matic two-speed transmission was introduced in 1959. A simplified version of the Cruise-O-Matic, it combined a torque connector and a compound planetary gear set. A front unit (multiple-disc) clutch provided high gear, a front band on the clutch drum provided low gear, and

6860-443: The next gear's sprag clutch assumes the torque transfer. The friction bands are often used for manually selected gears (such as low range or reverse) and operate on the planetary drum's circumference. Bands are not applied when the drive/overdrive range is selected, the torque being transmitted by the sprag clutches instead. The aforementioned friction bands and clutches are controlled using automatic transmission fluid (ATF), which

6958-681: The number of the highest gear used in that position (eg 3, 2 or 1). If these positions are engaged at a time when it would result in excessive engine speed, many modern transmissions disregard the selector position and remain in the higher gear. In descending order of the highest gear available: Many modern transmissions include modes to adjust the shift logic to prefer either power or fuel economy . "Sport" (also called "Power" or "Performance") modes cause gear shifts to occur at higher engine speeds, allowing higher acceleration. "Economy" (also called "Eco" or "Comfort") modes cause gear shifts to occur at lower engine speeds to reduce fuel consumption. Since

7056-416: The one-way sprag clutch (absent on Volga's transmission). The more powerful engine and thus torque required a liquid cooling system. Gear ratios were identical to GAZ-21, except for the torque converter, which had a maximum multiplication of 2.5. Both transmissions made a début in 1958 and 1959 respectively. Initially, it was planned that all of the privately owned Volgas be produced with the automatic, whilst

7154-402: The outer planet gears mesh with the ring gear. The primary sun gear (the small sun) meshes with the inner planets, and the secondary sun gear (large sun) meshes with the gears that turn with the outer planets. The right-most photo shows the other side of the carrier. Of the two meshing gears showing, the one on the right is slightly farther from the center of the carrier, allowing it to mesh with

7252-399: The patent was 1949, a time when pressure operated hydraulic technology was less well developed. Several years later, when the Ravigneaux went into production at Ford Motor Company, hydraulically operated band brakes and clutches were used. Ring gear B is coupled to planet gears S1, which are coupled to Sun M1. Ring R1 is coupled to planets S2, which are coupled to Sun C. Planet gears from

7350-533: The release of Ford's new FE and MEL engines. Although marketed as Cruise-O-Matic, the new transmissions were known internally as the MX (larger) and the FX (smaller). They were a three-speed design using a Ravigneaux planetary gearset like the original, but moved the pump from the rear to the front of the transmission, while also using a different valve body so the transmission would start in first gear as opposed to second. The MX

7448-548: The remaining transmissions. The new plant, called Fairfax Transmission Plant, was dedicated in 1950. The original Ford-O-Matic accomplished two things that Ford's two previous automatic transmissions failed to do: Through the use of an integrated torque converter and planetary gearset , Ford's automatic shifted smoothly without an interruption in torque from the engine. The other was the shifting pattern, revised from PNDLR to PRNDL, which served to reduce "shift shock" when changing gears and reduce "torque shock" when trying to rock

7546-429: The same, with the fourth being .67:1. The transmission featured a split-torque application for third gear, as well as a lockup in the torque converter. The project was shelved with a design that initially lacked a dampener in the torque converter, but after the project was revisited, a dampener ultimately made its way into the final design before Job 1. The XT-LOD was initially abandoned in 1966, but revisited in 1974 as

7644-414: The second system just going along for the ride with no load. The ratios depend on teeth counts and are taken from the example given in the patent. The photos on the right show the planet carrier from a Ford FMX automatic transmission . The planet carrier is the central part of a planetary gear set. Not shown are the two sun gears, called primary and secondary, that rotate within the carrier. Also not shown

7742-453: The select indicator externally resembled a manual transmission gearshift lever, and the cars even lacked a single brake pedal, instead having the "clutch"/brake pedal layout that dubbed each other. The GAZ-24 had the common cord-actuated parking brakes, thus the central shaft brake was removed and replaced by an extension housing to fit the shorter driveshaft of the GAZ-24. GAZ-24-24 would be produced alongside standard GAZ-24 until 1985. That year

7840-419: The small sun gear and co-rotate at a fixed gear ratio with respect to it. The outer planets couple with the large sun gear and co-rotates with a fixed gear ratio with respect to it. Finally, the ring gear also couples and co-rotates with the outer planets in a fixed gear ratio with respect to them. In contrast to a Ravigneaux, a simple planetary gear train has two concentric gears, one or more planets bridging

7938-424: The tests using a prescribed shifting pattern for manuals not always optimized for economy. However, on long highway journeys manual transmissions require maintaining a very specific cruising speed to optimise economy, making automatics preferable. The most common design of automatic transmissions is the hydraulic automatic, which typically uses planetary gearsets that are operated using hydraulics. The transmission

8036-605: The torque multiplication of the torque convertor at lower speeds. The Dynaflow was followed by the Packard Ultramatic in mid-1949 and the Chevrolet Powerglide for the 1950 model year. Each of these transmissions had only two forward speeds, relying on the converter for additional torque multiplication. In the early 1950s, BorgWarner developed a series of three-speed torque converter automatics for car manufacturers such as American Motors, Ford and Studebaker. Chrysler

8134-441: The two gear ratios available in the "Low" and "High" ranges and the clutch pedal was required for standing starts. It used a planetary gearset. The Chrysler Fluid Drive , introduced in 1939, was an optional addition to manual transmissions where a fluid coupling (similar to a torque-convertor, but without the torque multiplication) was added, to avoid the need to operate a manual clutch. The General Motors Hydra-Matic became

8232-418: Was among the first to have the basic gear selections ( park , reverse , neutral , drive , low ) which became the standard gear selection used for several decades. By the late 1960s, most of the fluid-coupling two-speed and four-speed transmissions had disappeared in favor of three-speed units with torque converters. Also around this time, whale oil was removed from the automatic transmission fluid. During

8330-523: Was built in the Livonia Transmission Plant in Livonia, Michigan and was placed behind the more powerful engines in Mercury, Lincoln, and select Ford models. The smaller FX was built alongside the Ford-O-Matic at the Fairfax Transmission Plant and was put in midrange Ford and Mercury models. Because the original Ford-O-Matic started in second rather than first, it was marketed as a two-speed after

8428-613: Was called the Controlled Coupling Hydra-Matic , or "Jetaway" transmission. The original Hydra-Matic remained in production until the mid-1960s at GM, with the licensed Rolls-Royce Automatic transmission soldiering on until 1978 on the Rolls-Royce Phantom VI . In 1964, General Motors released a new transmission, the Turbo Hydramatic , a three-speed transmission which used a torque convertor. The Turbo Hydramatic

8526-501: Was followed by various eastern European tractors through the 1970s (using manual operation via a single clutch pedal), then the Porsche 962 C racing car in 1985. The first DCT of the modern era was used in the 2003 Volkswagen Golf R32 . Since the late 2000s, DCTs have become increasingly widespread, and have supplanted hydraulic automatic transmissions in various models of cars. Automated manual transmission (AMT) , sometimes referred to as

8624-503: Was installed to the left of the steering wheel. In 1959 the keyboard control was discontinued and used a steering column gear selector lever. In the mid-1950s, cars began to grow in size, and in response to heavier vehicles, more powerful engines were being developed. The original Ford-O-Matic was used as a template when developing the next automatic transmissions for Ford; in fact, many of the gear sets are interchangeable. The new transmissions arrived for model year 1958 which coincided with

8722-541: Was introduced in the 1955 Citroën DS , which used a 4-speed BVH transmission. This semi-automatic transmission used an automated clutch, which was actuated using hydraulics . Gear selection also used hydraulics , however, the gear ratio needs to be manually selected by the driver. This system was nicknamed Citro-Matic in the U.S. The first modern AMTs were introduced by BMW and Ferrari in 1997, with their SMG and F1 transmissions, respectively. Both systems used hydraulic actuators and electrical solenoids , and

8820-631: Was introduced with the Hudson Commodore in 1942, called Drive-Master . This unit was an early semi-automatic transmission , based on the design of a conventional manual transmission, which used a servo -controlled vacuum -operated clutch system, with three different gear shifting modes, at the touch of a button; manual shifting and manual clutch operation (fully manual), manual shifting with automated clutch operation (semi-automatic), and automatic shifting with automatic clutch operation (fully automatic). Another early example of this transmission system

8918-532: Was late in developing its own true automatic, introducing the two-speed torque converter PowerFlite in 1953, and the three-speed TorqueFlite in 1956. The latter was the first to utilize the Simpson compound planetary gearset. In 1956, the General Motors Hydra-Matic (which still used a fluid coupling) was redesigned based around the use of two fluid couplings to provide smoother shifts. This transmission

9016-555: Was produced from 1977 until 1989. In 1981 GAZ launched what was to be a successor to the GAZ-24, but separated into a separate model and built alongside the -24, the GAZ-3102 Volga. It too gained a "chaser" modification – GAZ-31013 with the 220 hp engine from the GAZ-14, and its transmission, adapted to Volga's body. This model was built until 1996 in tiny numbers, for the VIP security detail only. As only partial statistics have been published, it

9114-533: Was regulated by a lever linked to the accelerator pedal). A kick-down feature was also present. First gear could only be engaged manually in Low (though it could be engaged if the car was in motion, but would only downshift) and was used for engine braking or rapid starts. Gear ratios were: 2.4 – 1.0 for the torque converter, 2.84 for first gear, 1.68 for second, third was direct and reverse was 1.72. Chaika's Cruise-O-Matic copy required fewer adaptations, due to its mating with

9212-419: Was removed, but unlike the sedan, it now had a parking pin. The floor-mounted selector got an international P-R-N-D-2-1 lettering. Regime "1" now operated first gear only, via the rear band, whilst regime "2" locked out the first gear (like on the original GAZ-21 Volga). Gear ratios were now 2.35 – 1.0 for torque converter, 2.64 for first gear, 1.55 for second, third remained direct, and reverse became 2.0. The car

9310-422: Was replaced by GAZ-24 and the V8 adoption followed soon, dubbed GAZ-24-24. As the sedan's standard gearbox was now a four on the floor manual, the selector lever was accordingly altered. Unofficially these cars were called "Chasers", and despite their novelty, the engine torque was disproportional to the chassis ability. This meant a low service life and also required very professional driving. For concealment reasons

9408-522: Was replaced by the C4 in 1964. Ultimately the transmission Ford licensed to build from Warner Gear/B-W was less expensive to build than the Detroit Gear/B-W unit that Ford had initially sought to license from Studebaker. When Studebaker ran into financial difficulty in the mid-1950s, Studebaker turned to Ford and licensed the less expensive Ford-O-Matic, rebranded it as the Flight-O-Matic, and dropped

9506-551: Was using a hand lever, helical gears were used (to reduce noise) and the gears used a constant-mesh design. A planetary gearset was also used in the 1908 Ford Model T , which was fitted with a two-speed manual transmission (without helical gears). An early patent for the automatic transmission was granted to Canadian inventor Alfred Horner Munro of Regina in 1923. Being a steam engineer, Munro designed his device to use compressed air rather than hydraulic fluid , and so it lacked power and never found commercial application. In 1923,

9604-426: Was working on at his previous employer. Ford and the Warner Gear division of Borg-Warner signed a contract in 1948 which entered B-W into a supply agreement wherein they would build half of Ford's transmissions for five years, with the other half either being built by Ford or by a different supplier. Because of this agreement, Ford licensed the design themselves and broke ground immediately on an assembly plant to build

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