Mid-2000s BMW SMG-III shifter, with a selector for the shift speed located below the shifter

The automated manual transmission (AMT) is a type of transmission for motor vehicles. It is essentially a conventional manual transmission[1][2][3][4][5] equipped with automatic actuation to operate the clutch and/or shift gears.

Many early versions of these transmissions that are semi-automatic in operation, such as Autostick, which automatically control only the clutch – often using various forms of clutch actuation, such as electro-mechanical, hydraulic, pneumatic, or vacuum actuation[6][7] – but still require the driver's manual input and full control to initiate gear changes by hand. These systems that require manual shifting are also referred to as clutchless manual systems.[8] Modern versions of these systems that are fully automatic in operation, such as Selespeed and Easytronic, can control both the clutch operation and the gear shifts automatically, by means of an ECU, therefore requiring no manual intervention or driver input for gear changes.[9][10]

The usage of modern computer-controlled AMTs in passenger cars increased during the mid-1990s, as a more sporting alternative to the traditional hydraulic automatic transmission. During the 2010s, AMTs were largely replaced by the increasingly widespread dual-clutch transmission, but remained popular for smaller cars in Europe and some developing markets, particularly India, where it is notably favored over conventional automatic and CVT transmissions due to its lower cost.[11]

Design and operation

Automated manual transmissions can be semi-automatic or fully-automatic in operation. Several different systems to automate the clutch and/or shifting have been used over the years, but they will generally use one of the following methods of actuation for the clutch and/or shifting: hydraulic or electro-hydraulic actuation,[12] electro-mechanical,[13] pneumatic,[6][14][15] electromagnetic,[16][17][18] or even purely electrical using an electric motor.

Gear shifting, clutch actuation, shift-timing, and rev-matching are all under automated control via electronic sensors, computers, and actuators.[13][19] When shifting gears, the driver selects the desired gear with the transmission shift lever, while electronic sensors and actuators connected to a TCU (transmission computer) or microprocessor will automatically operate the clutch and throttle to match revs and to re-engage the clutch in milliseconds. Torque and power transfer to the drive wheels will also be electronically controlled. Most modern implementations of this transmission function are in a sequential mode, where the driver can upshift or downshift by only one gear at a time. However, this is not the case for all modern transmissions. For example, BMW's "SMG" and Ferrari's "F1" transmission can skip gears on both downshifts and upshifts, when selecting gears manually via the steering wheel-mounted paddle-shifters, as seen on most modern transmissions. Older clutchless manual transmissions (mostly prior to the 1990s) will retain H-pattern shifters, plus the shift gate, and will require the driver to select the required gear ratios manually. The clutch, however, will be a servo-controlled unit, connected to various actuators, a solenoid and sensors which control the clutch automatically.

Another alternate means of clutch automation is the "clutch-by-wire" system. The system generally uses an electric actuator and electronic sensors, which replace the mechanical clutch linkage or hydraulic clutch connection, to monitor and control clutch positioning, completely replacing the hydraulic linkage between the mechanical clutch and pedal itself with a single electro-mechanical actuator.[20][21][22]

Depending on the mechanical build and design, some (mostly modern) automated manual transmissions will automatically shift gears at appropriate points (like a conventional automatic transmission), while traditional semi-automatic and clutchless manuals require the driver to manually select the gear even when the engine is at redline, since they automate only part of the transmission (namely the clutch), and will not shift gears by themselves.[23] Despite the superficial similarity, automated manual transmissions differ significantly in internal operation and driver's "feel" from a manumatic, the latter of which is an automatic transmission (automatics use a torque converter instead of a clutch like in an automated manual, to manage the mechanical linkage between the transmission and motor) with the ability to override the automatic transmission's computer, and actuate shifts manually.[24]

Add-on AMTs can also function as a regular manual gearbox (with a manual shift lever), whereas integrated AMTs do not need a "normal" shift layout, so they can be designed with an optimized AMT shifting layout (which would have an unusual pattern to manually shift). Integrated AMTs either have gear-selector drums (which allows only serial shifting and no gear-skipping, but this system is fairly inexpensive, because it needs only one actuator), or single actuators. Single-actuator systems require one actuator for each shifting sleeve (which is why this type of system is more expensive, but it also shifts faster). The actuators can either be electro-hydraulic (more expensive, but faster, well-suited for single-actuator systems, and allow for higher torque), or electro-mechanical (less expensive, but usually limited to 250 N·m (184.5 lb-ft) of gearbox input torque). This limit is because the clutch actuation force increases with higher torque, and short shifting times; electro-mechanical actuators are just electric motors – using larger motors reduces the motor dynamics due to the motors' higher mass moment of inertia (which is not good for fast shifting), and bigger motors also put more stress on the car's 12-volt electrical system. As a result, one can have either slow shifting and a very large lead-acid battery (not suitable for cars), or fast shifting and a smaller battery (works up to 250 N·m of torque).

Modern AMTs, such as Suzuki Auto Gear Shift and Dacia/Renault Easy-R, usually operate in conjunction with electronic throttle control to initiate gear shifts based on certain RPM and/or throttle position.

Usage in passenger cars

2000-2006 BMW SMG-II shifter

The automated manual transmission has its origins in early clutchless manual transmissions that began to appear on mass-production cars in the 1940s and 1950s. An early example of this transmission 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).[25][7][26]

Another early example is 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. The 1956 Renault Dauphine 3-speed manual transmission was available with an optional Ferlec automated clutch, which used an electromagnetically-operated clutch system.[27][28] Other clutchless manual transmissions included the 1967 NSU Ro 80 (3-speed Fichtel & Sachs) and 1967 Porsche 911 (4-speed Sportomatic), both of which used vacuum-actuated clutches and hydraulic torque converters. The 1968 Volkswagen Beetle and Volkswagen Karmann Ghia offered a 3-speed Autostick transmission, which used an electric switch on the gear shifter connected to a solenoid, to operate the electro-pneumatic vacuum clutch servo.[29][30]

In 1963, Renault switched from the automated clutch to a fully-automatic 3-speed Jager transmission, which consisted of an electro-mechanical control unit that operated both the clutch and shifting, effectively making it one of the earliest automated manual transmissions.[31][32][33] The Jager transmission was controlled via dash-mounted electronic push-buttons.[34]

The Isuzu NAVi5 5-speed automatic transmission was introduced in the 1984 Isuzu Aska mid-size sedan (sold in the Japanese domestic market only). This transmission, originally designed for trucks, was based on a manual transmission with the addition of hydraulic actuators for the gear shifter and the clutch. Initial versions did not allow direct selection of gear ratios, instead allowing drivers only to lock out higher gears (as per many traditional automatic transmissions). Later versions added a manual mode, allowing the driver to control the gear selection.

Several companies owned by Fiat S.p.A. were influential in the development of automated manual transmissions. Ferrari's involvement with automated manual transmission began with the 7-speed semi-automatic paddle-shift transmission used in the 1989 Ferrari 640 Formula One racing car. In 1992, the Ferrari Mondial T introduced the option of a "Valeo" 5-speed semi-automatic transmission.[35] This transmission used an electro-mechanical actuator to automatically operate the clutch,[36] while the gearshift mechanism was a standard H-pattern shifter operated as per normal transmissions.[37] In 1997, the Ferrari F355 became available with an "F1" 6-speed transmission, which uses paddle-shifters located behind the steering wheel or can be driven in a fully-automatic mode.[38] The F355's successors offered similar transmissions,[39] until the company switched to a dual-clutch transmission for the Ferrari 458 in 2009.

Ferrari F430 F1 steering wheel with paddle-shifters

Sister company Alfa Romeo introduced the related Selespeed 5-speed automatic transmission for the Alfa Romeo 156 in 1999.[40][41] This was followed by Maserati's 2001 introduction of the related Cambiocorsa 6-speed automatic transmission in the Maserati Coupé.[42] Selespeed was also used in the Fiat Punto and Stilo models.

BMW's involvement with automated manual transmissions began in 1993, when the "Shift-tronic" 6-speed semi-automatic was offered on the Alpina B12 coupe (based on the E31 850CSi).[43][44] Using an automated clutch paired to a standard H-pattern shifter (as per the Ferrari Mondial T), the transmission was supplied by LuK and fitted to less than 40 cars.[45] Mass-production of automated manual transmissions began for BMW in 1997 with the introduction of the "SMG" 6-speed automatic transmission in the E36 M3 coupe.[46] Although the name "SMG" was an abbreviation of "Sequential Manual Gearbox", the transmission internal were as per a typical (synchromesh-equipped) manual transmission, not a true sequential manual transmission. The SMG was replaced by the SMG-II when the E46 M3 was introduced in 2000.[47] BMW's final AMT (before being replaced by a dual-clutch transmission) was the 7-speed SMG-III used in the 2004-2010 BMW E60 M5 and related BMW E63 M6. The SMG-III could achieve a shift time of 65 milliseconds in its most aggressive mode[48]

From 2002 to 2007, the third-generation Toyota MR2 was available with an "SMT" 6-speed automated manual transmission. The SMT system utilized an electro-hydraulic activation system for both the clutch and shifting, but no H-pattern shifter like with the standard transmission. Instead, there was a shift lever that could be pulled and pushed forward or backward to upshift and downshift, as well as the addition of electronic steering-wheel-mounted shift buttons.

Brands within the Volkswagen Group have typically used dual-clutch transmissions instead of automated manual transmissions, however a 6-speed "E-gear" automated manual transmission was introduced for the 2004 Lamborghini Murciélago.[49] and Lamborghini Gallardo.[50][51] The E-gear was used on the successors to the Murciélago and Gallardo, and it was also available on the 2007-2012 Audi R8 (Type 42), marketed as the "R-tronic" transmission.[52][53][54]


Year of
Manufacturer Transmission Name Model(s)
1996 Alfa Romeo Selespeed 156, 147, GT, 159, Brera, Spider
2007 Q-Select 8C Competizione / 8C Spider
2001 Aston Martin SSM Vanquish
2005 Sportshift Vantage (2005)
2009 - One-77[55]
2020 - Valkyrie
1999 Audi - A2
2006 Audi R-Tronic R8 (Type 42)[56][57]
1997 BMW SMG E36 M3[58]
2000 SMG-II E46 M3, E46 3 Series, E85 Z4, E60 5 Series, E63 6 Series
2004 SMG-III E60 M5, E63 M6[59]
2003 Chery - QQ3,
2009 - M1
1955 Citroën BVH DS[60]
1976 C-Matic CX, GS[61]
2004 EGS C1, C4
2003 Sensodrive C2, C3
2011 - DS5
2016 - C6 (China)
2015 Dacia Easy-R Logan, Sandero, Duster
2017 Dallara - Stradale
1993 Fiat Selespeed Punto, Stilo, Grande Punto
1995 Dualogic Bravo, Idea, Palio, Punto, Siena, Uno, Panda, 500L, Doblò, Linea
1997 Citymatic Seicento
2007 Comfort-Matic Fiorino
2018 GSR Argo, Cronos, Mobi
1988 Ferrari Valeo Mondial T
1994 F1 355 F1, 360, 575M Maranello, Enzo, 612 Scaglietti, F430, FXX, 599
2004 Ford Europe Durashift EST Fusion, Fiesta, Transit
2010 Honda I-SHIFT Civic, Jazz
1942 Hudson Drive-Master Commodore
1950 Supermatic Commodore[62][63]
2018 Hyundai Smart Auto AMT[64] i10, Aura, Santro
2020 iMT Venue,[65] i20
1984 Isuzu NAVi5 Aska, Gemini
2020 Kia iMT Sonet, Seltos
2007 LADA (AvtoVAZ) - Priora
2015 - Xray, Vesta
2004 Lamborghini e-gear Murciélago, Gallardo, Reventón, Sesto Elemento
2011 ISR Aventador, Veneno, Centenario, Sián, Countach LPI 800-4
2004 Lancia DFN Musa, Ypsilon
2004 Maxus (LDV) - Maxus V80, Maxus V90
2010 Lexus ASG LFA
2015 Mahindra Autoshift TUV300
2019 - XUV300
2001 Maserati Cambiocorsa Coupé and Spyder, MC12
2003 DuoSelect Quattroporte V
2007 MC-Shift GranTurismo
1999 Mercedes-Benz - A-Class (W168)
2000 Sequentronic[66] CLK-Class (C208)
2001 C-Class (W203) & C SportCoupé (CL203)
2001 E-Class (W211)
2001 SL 350 (R230)
2002 CLK-Class (C209)
2021 Mercedes-AMG - ONE
2004 Mitsubishi AllShift Colt
1967 NSU - Ro 80
1999 Pagani - Zonda
2011 - Huayra
2005 Peugeot 2-Tronic 107, 1007
2014 Polaris AutoDrive Slingshot
1967 Porsche Sportomatic 911[67][68]
2005 Proton AMT Savvy
1956 Renault - Dauphine
2001 Quickshift Modus, Twingo
2015 Easy-R Kwid, Symbol III, Triber
1994 Saab Sensonic 900 NG[69][70][71][72][4]
2012 SEAT ASG Mii
2011 ŠKODA ASG Citigo
1998 Smart Softouch Fortwo, Forfour, Roadster
2013 Spania - GTA Spano
2004 SSC North America - Ultimate Aero
2020 - Tuatara
2014 Suzuki/Maruti AGS Celerio
2017 AGS Swift Dzire, Ignis
2004 - Swift
2014 - Alto, Wagon R (India, Pakistan & Indonesia)
2008 Tata Motors Easy Shift Nano
2017 Hyprdrive SSG Nexon, Tiago, Tigor
1999 Toyota SMT MR2 (W30)
2005 MMT Aygo, Yaris, Corolla, Corolla Verso, Mark X, Auris[73]
1965 VEB Sachsenring Hycomat Trabant 601
2004 Opel/Vauxhall Easytronic Corsa, Tigra, Meriva, Astra, Zafira, Vectra, Adam
1968 Volkswagen Autostick Beetle, Karmann Ghia[74][75]
1998 - Lupo
2009 I-Motion Gol, Voyage
2011 ASG Up, Fox
2009 Zenvo - ST1

Usage in Semi-trailer trucks / Tractor units

See also


  1. ^ 5 Transmissions - Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles. 2015. doi:10.17226/21744. ISBN 978-0-309-37388-3. Retrieved 26 July 2020. ((cite book)): |website= ignored (help)
  2. ^ Yulong, Lei; Hua, Tian (11 April 2005). "Research on Accurate Engagement Control of Electrohydraulic Clutch Actuator". www.sae.org. SAE Technical Paper Series. 1. doi:10.4271/2005-01-1787. Retrieved 26 July 2020.
  3. ^ "Transmission Actuation" (PDF). www.fte-automotive.com. Archived from the original (PDF) on 3 November 2022. Retrieved 26 July 2020.
  4. ^ a b "Manual Transmission". www.autozine.org. Retrieved 26 July 2020.
  5. ^ "Manual vs Automatic Transmission: A Shift to Know About". 6 May 2020.
  6. ^ a b "ProductFinder Commercial Vehicles - ZF". www.zf.com.
  7. ^ a b Drivemaster Service Information hudsonterraplane.com
  8. ^ "Hyundai Created a Clutch-less Manual Transmission". 10 July 2020.
  9. ^ "Directly from the Formula 1". www.magnetimarelli.com. Retrieved 26 July 2020.
  10. ^ "Introduction to Automatic Transmission Systems". www.tranzmile.com. Archived from the original on 19 March 2023. Retrieved 1 August 2020.
  11. ^ Desk, HT Auto (22 March 2022). "AMT or CVT: Which automatic transmission technology is better?". HT Auto. Retrieved 20 November 2023.
  12. ^ "Clutch Actuation System Car". aftermarket.zf.com.
  13. ^ a b "Automated Manual Transmission". ZF. Archived from the original on 26 September 2020. Retrieved 27 February 2020.
  14. ^ Clutch Actuator mme-motorsport.com
  15. ^ "European publication server".
  16. ^ "Electromagnetic Actuators". 19 September 2015.
  17. ^ "Electromagnetic Clutch".
  18. ^ Automatic Electromagnetic Clutch 123seminarsonly.com
  19. ^ "Automatic Transmission Types Explained: CVT, DSG, Tiptronic, Dual-Clutch, Automated-Manual Transmission". www.carfromjapan.com. 11 November 2017. Retrieved 1 August 2020.
  20. ^ "What is a clutch-by-wire system? PH Explains".
  21. ^ "Clutch-by-Wire".
  22. ^ Kupplungs System zf.com
  23. ^ "What are the different types of transmissions?". www.edmunds.com. Archived from the original on 5 August 2020. Retrieved 1 August 2020.
  24. ^ Electric Gearshift Actuator - MAGNETI MARELLI
  25. ^ "HowStuffWorks "1942 Hudson"". Archived from the original on 20 August 2008.
  26. ^ "HowStuffWorks "1950 Hudson Commodore"". Archived from the original on 4 July 2008.
  27. ^ "1956-1968 Renault Dauphine". www.howstuffworks.com. 20 August 2007. Retrieved 2 August 2020.
  28. ^ "Renault Dauphine buyer's guide: what to pay and what to look for". www.classicandsportscar.com. Retrieved 2 August 2020.
  29. ^ "Shift This: A History of Porsche's Sportomatic, Tiptronic, and PDK Transmissions". 10 December 2013.
  30. ^ "From the Archive: 1968 Porsche 911 Sportomatic". Car and Driver. 1 January 1970.
  31. ^ A. Dubois Dumée (October 1998). Renault, 100 ans moteur d'ideés: Le magazine du centenaire. Renault.
  32. ^ Blunsden, John (October 1962). "Paris salongen" [The Paris Salon]. Illustrerad Motor Sport (in Swedish). No. 10. Lerum, Sweden. p. 12.
  33. ^ "Vive La Difference! - 1965-1971 Renault 10". www.hemmings.com. Retrieved 2 August 2020.
  34. ^ "Renault Dauphine advertisement". Life Magazine (4 October 1963): 23.
  35. ^ Batchelor, Dean. Illustrated Ferrari Buyer's Guide (4 ed.).
  36. ^ "Actuator range: Reduction of mechanical/Thermal losses".
  37. ^ "Ferrari Mondial review". www.youtube.com. Archived from the original on 21 December 2021. Retrieved 29 July 2020.
  38. ^ "The Ferrari Automated Gearbox". www.ferrari.com. Retrieved 29 July 2020.
  39. ^ Neff, John (18 July 2007). "Ferrari reveals F430 Scuderia, not Challenge Stradale". Autoblog.com. Retrieved 3 October 2009.
  40. ^ Ciferri, Luca (13 December 2005). "FERRARI LAUNCHES F1-STYLE GEARBOX ON F355". Automotive News Europe. Retrieved 12 June 2018.
  41. ^ "Directly from the Formula 1. - Magneti Marelli". Magneti Marelli. Retrieved 26 March 2020.
  42. ^ "Maserati Spyder Cambiocorsa - First Drive". www.roadandtrack.com. Archived from the original on 13 August 2011.
  43. ^ "Milestones: ALPINA Automobiles". www.alpina-automobiles.cz. Retrieved 30 July 2020.
  44. ^ "Gaze at this achingly desirable Alpina B12 5.7 Coupe". www.topgear.com. 21 January 2020. Retrieved 30 July 2020.
  45. ^ "The Automated Clutch - The New LuK ECM" (PDF). www.schaeffler.com. Archived from the original (PDF) on 1 April 2019. Retrieved 30 July 2020.
  46. ^ "1992-2000 E36 BMW M3 Review". www.topspeed.com. 28 June 2006. Retrieved 30 July 2020.
  47. ^ "BMW 330i SMG". evo.co.uk. Retrieved 8 May 2007.
  48. ^ Lewin, Tony (30 September 2016). The BMW Century: The Ultimate Performance Machines. Motorbooks. p. 137. ISBN 9780760353042. Retrieved 21 July 2017.
  49. ^ "2004 Lamborghini Murcielago Base Coupe full range specs". www.automobile-catalog.com. Retrieved 31 July 2020.
  50. ^ "Lamborghini Gallardo Review, Pricing and Specs". www.caranddriver.com. 13 May 2019. Retrieved 26 July 2020.
  51. ^ "2006 Lamborghini Gallardo Spyder". www.caranddriver.com. 1 March 2006. Retrieved 26 July 2020.
  52. ^ "2008 Audi R8". www.caranddriver.com. 1 April 2007. Retrieved 26 July 2020.
  53. ^ "2008 Audi R8 - The Everyday Supercar". www.youtube.com. Car and Driver. Retrieved 26 July 2020.
  54. ^ "2008 Audi R8". www.caranddriver.com. 1 January 2007. Retrieved 26 July 2020.
  55. ^ "Aston Martin One-77 review and pictures". www.evo.co.uk. Retrieved 1 August 2020.
  56. ^ "Audi R8 Powertrain". www.howstuffworks.com. 3 June 2010. Retrieved 26 July 2020.
  57. ^ "2010 Audi R8 5.2 FSI V10 Quattro R Tronic". www.caranddriver.com. 22 February 2010. Retrieved 26 July 2020.
  58. ^ "FAQ E36 M3 3.2". BMW M Registry. Retrieved 3 October 2009.
  59. ^ ST 813 M DCT Drivelogic. BMW AG. p. 7. Retrieved 14 July 2019.
  60. ^ "Chas' Hydraulic Course" (PDF). www.mycitroen.dk. Retrieved 26 July 2020.
  61. ^ "Semi-Automatic Transmission".
  62. ^ Hudson Owner Manual hudsonterraplane.com
  63. ^ "How Hudson Cars Work". howstuffworks.com. 20 June 2007.
  64. ^ Archived at Ghostarchive and the Wayback Machine: "Hyundai | Service Tips | Smart Auto AMT". YouTube.
  65. ^ "Hyundai Venue Offers Manual Transmission with No Clutch Pedal". 10 July 2020.
  66. ^ "Press Information October 17, 2000". mercedes-benz-publicarchive.com. Retrieved 28 November 2023.
  67. ^ "Automatic gearbox: A Porsche 911 history". www.total911.com. 7 May 2015. Retrieved 26 July 2020.
  68. ^ "Shift This: A History of Porsche's Sportomatic, Tiptronic, and PDK Transmissions". www.caranddriver.com. 10 December 2013. Retrieved 26 July 2020.
  69. ^ "For $10,000, Come To Your Sensonics". www.jalopnik.com. 14 November 2013. Retrieved 26 July 2020.
  70. ^ "Über Rare Saab 900 NG Sensonic (Clutchless) edition". www.saabplanet.com. 19 October 2014. Retrieved 26 July 2020.
  71. ^ "Saab shelves Sensonic transmission". www.autonews.com. 16 February 1998. Retrieved 26 July 2020.
  72. ^ "Saab develops stick with no clutch". www.OrlandoSentinel.com. Retrieved 26 July 2020.
  73. ^ "Toyota Auris, Yaris – MMT Clutch Replacement Guide (6 speed)" (PDF). oscaro.media. Retrieved 1 October 2023.
  74. ^ "Curbside Classic: 1968 Volkswagen Automatic Stickshift – Chrysler's Fluid Drive Returns in the Safer Käfer". 17 June 2017.
  75. ^ "Autostick".
  76. ^ "Volvo Trucks Egypt".
  77. ^ "Leading Transmission Maker Predicts Major Shift to Automatics in Heavy Vehicles - AutoWeb News". Autoweb.com.au. Archived from the original on 27 July 2014. Retrieved 18 July 2014.
  78. ^ New quester brochure Archived 2021-07-02 at the Wayback Machine
  79. ^ "History". Udtrucks.com. Retrieved 20 March 2022.