Torsen Torque-Sensing (full name Torsen traction) is a type of

limited-slip differential A limited-slip differential (LSD) is a type of differential gear train that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the ...

used in

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

s. It was invented by American Vernon Gleasman and manufactured by the Gleason Corporation. Torsen is a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of Torque-Sensing. ''TORSEN'' and ''TORSEN Traction'' are registered

trademark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a Good (economics and accounting), product or Service (economics), service f ...

s of

JTEKT JTEKT Corporation TYO: 6473.T is a Japanese corporation created in January 2006 upon the merger of two companies: Koyo Seiko Co. and ''Toyoda Machine Works''. Toyoda Machine Works, Machine tool sales for North, Central and South America, afterm ...

Torsen North America Inc (formerly Zexel Corporation, formerly Gleason Power Systems). All Torsen differentials have their origin in the Dual-Drive Differential that was invented and patented by Gleasman in 1958.

Use

Torsen differentials can be used in one or more positions on a

motor vehicle A motor vehicle, also known as a motorized vehicle, automotive vehicle, automobile, or road vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on railway track, rails (such as trains or trams), does not fly (such ...

: * center—used to apportion

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

appropriately between front and rear axles on an

all-wheel drive An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand. Types The most common forms of all-wheel drive are: ;1x1 : All unicycles Reflects one axle with ...

vehicle. * rear—used to apportion torque appropriately between left and right sides in rear axles. This may be on either a

rear-wheel drive Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-whee ...

or a four-wheel drive vehicle. * front—used to apportion torque appropriately between left and right sides in front axles. This may be on either a

front-wheel drive Front-wheel drive (FWD) is a form of internal combustion engine, engine and transmission (mechanics), transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature ...

or a four-wheel drive vehicle. A four-wheel-drive vehicle, for example, may use one, two, or three Torsen differentials.

Types

, there are three types of Torsen differentials. # The original ''Torsen T-1 (Type A)'' uses crossed axis helical gears to limit torque split. The Type I can be designed for higher torque bias ratios than the Type II, but typically has higher backlash and the potential for noise, vibration, and harshness (NVH) issues, and requires a precise setup/installation. # The later ''Torsen T-2 (Type B)'' uses a parallel gear arrangement to achieve a similar effect. There is also a specialist application of the T-2, known as the ''T-2R (RaceMaster)''. # The latest ''Torsen T-3 (Type C)'' is a planetary type differential, in that the nominal torque split is not 50:50. The Type C is available as single or twin version; the Torsen twin C differential has front and center differential in the same unit. The Torsen T-3 is currently employed as the center differential in all non- Haldex Traction

Audi Audi AG () is a German automotive manufacturer of luxury vehicles headquartered in Ingolstadt, Bavaria, Germany. A subsidiary of the Volkswagen Group, Audi produces vehicles in nine production facilities worldwide. The origins of the compa ...

models with a ZF-sourced automatic transmission Quattro

four-wheel drive A four-wheel drive, also called 4×4 ("four by four") or 4WD, is a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case pr ...

, such as: Audi A6, Audi A7, and Audi Q7. Audi uses a mechanical "Crown Wheel" center differential for all longitudinal implementations using dual-clutch transmissions, such as the 2013/14 S4/RS4.

Alfa Romeo Alfa Romeo Automobiles S.p.A. () is an Italian carmaker known for its sports-oriented vehicles, strong auto racing heritage, and iconic design. Headquartered in Turin, Italy, it is a subsidiary of Stellantis Europe and one of 14 brands of mu ...

used a Torsen C twin differential in the Alfa Romeo 156 Crosswagon Q4 and also in the 159, Alfa Romeo Brera and Spider Q4 models. Also,

Toyota is a Japanese Multinational corporation, multinational Automotive industry, automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on August 28, 1937. Toyota is the List of manuf ...

uses a Torsen T-3 in the center differential of the 4Runner Limited, FJ Cruiser 6-speed manual, Sequoia, Land Cruiser, Land Cruiser Prado and Lexus GX470, with manual locking feature, and

General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...

used a Torsen T-3 center differential in the transfer case of the Chevrolet TrailBlazer SS and

Saab 9-7X The Saab 9-7X is a compact luxury crossover SUV that was manufactured by General Motors for the American market and marketed under the Saab Automobile, Saab marque, then owned by GM. The 9-7X was first presented at the New York International Auto ...

(Aero model only).

Behaviour of Torsen differentials

The Torsen differential works just like a conventional differential, but can lock up if a torque imbalance occurs, the maximum ratio of torque imbalance being defined by the torque bias ratio (TBR). When a Torsen has a 3:1 TBR, that means that one side of the differential can handle up to while the other side would have to only handle of applied torque. During acceleration under asymmetric traction conditions, so long as the higher traction side can handle the higher applied torque, no relative wheelspin will occur. When the traction difference exceeds the TBR, the slower output side of the differential receives the tractive torque of the faster wheel multiplied by the TBR; any extra torque remaining from applied torque contributes to the

angular acceleration In physics, angular acceleration (symbol α, alpha) is the time rate of change of angular velocity. Following the two types of angular velocity, ''spin angular velocity'' and ''orbital angular velocity'', the respective types of angular accele ...

of the faster output side of the differential. The TBR should not be confused with the uneven torque-split feature in the planetary-type Torsen III. The planetary gearset allows a Torsen III center differential to distribute torque unevenly between front and rear axles during normal (full traction) operation without inducing wind-up in the drivetrain. This feature is independent of the torque bias ratio.

Torsens in front and/or rear axles

When a vehicle is in a turn, the outer wheel will rotate faster than the inner wheel. Friction in the differential will oppose motion, and that will work to ''slow'' the faster side and ''speed up'' the slower/inner side. This leads to asymmetric torque distributions in drive wheels, matching the TBR. Cornering in this manner will reduce the torque applied to the outer tire, leading to possibly greater cornering power, unless the inner wheel is overpowered (which is easier to do than with an open differential). When the inner tire (which has less traction due to weight transfer from lateral acceleration) is overpowered, it angularly accelerates up to the outer wheel speed (small percent wheel spin) and the differential locks, and if the traction difference does not exceed the TBR, the outer wheel will then have a higher torque applied to it. If the traction difference exceeds the TBR, the outer tire gets the tractive torque of the inner wheel multiplied by the TBR, and the remaining applied torque to the differential contributes to wheel spin up. When a Torsen differential is employed, the slower-moving wheel always receives more torque than the faster-moving wheel. The Torsen T-2R RaceMaster is the only Torsen to have a preload

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

. So, even if a wheel is airborne, torque is applied to the other side. If one wheel were raised in the air, the regular Torsen units would act like an open differential, and no torque would be transferred to the other wheel. This is where the parking brake "trick" can help out. If the parking brake is applied, assuming that the parking brake applies even resistance to each side, then the drag to the airborne side is "multiplied" through the differential, and TBR times the drag torque is applied to the other side. So, the ground side would see (TBR X drag torque) minus drag torque, and that may restore motion either forward or in reverse. In Hummer/ HMMWV applications, there are both front and rear Torsen differentials, so the use of the main brakes will operate this "trick" on both axles simultaneously.

Torsen users

Torsen differentials are used in many of the various

quattro models, excluding the A3 and S3 and TT, which have transverse-mounted engines and use Haldex Traction 4WD systems. It is also used in the third- and fourth-generation Toyota Supra (Optional) and third-generation Toyota Soarer, the B5 platform revision of the

Volkswagen Passat The Volkswagen Passat is a nameplate of D-segment, large family cars (D-segment) manufactured and marketed by the German automobile manufacturer Volkswagen since 1973 and also marketed variously as the Dasher, Santana, Quantum, Magotan, Corsar ...

4motion (based upon the

Audi A4 The Audi A4 is a line of luxury compact executive cars produced from 1994 to 2025 by the German car manufacturer Audi, a subsidiary of the Volkswagen Group. The A4 has been built in five generations and is based on the Volkswagen Group B platfor ...

), Mazda MX-5/Miata 1994 to 1995 have a Torsen Type I and late 1995 to 2002 models have a Torsen Type II, the 2002-2003 model year of the Nissan Maxima SE 6 speed manual, the

Honda S2000 The Honda S2000 is a Mid-engine design, front-mid engine Roadster (automobile), open top sports car that was manufactured by Japanese automobile manufacturer Honda, from 1999 until 2009. First shown as a concept car called the SSM at the Tokyo Mo ...

, and 1999-2002 S15 Nissan Silvia Spec R. The Lancia Delta Integrale, the

Peugeot 405 The Peugeot 405 is a large family car manufactured by the French automaker Peugeot from 1987 to 1997. Its production continued under license from outside Europe in Iran by Iran Khodro Company until 2020. It was voted European Car of the Year for 1 ...

T16, as well as the 1999-2002 model

Pontiac Firebird The Pontiac Firebird is an American automobile built and produced by Pontiac (automobile), Pontiac from the 1967 to 2002 model years. Designed as a pony car to compete with the Ford Mustang, it was introduced on February 23, 1967, five months a ...

and

Chevrolet Camaro The Chevrolet Camaro is a mid-size American automobile manufactured by Chevrolet, classified as a pony car. It first went on sale on September 29, 1966, for the 1967 model year and was designed to compete with the Ford Mustang. The Camaro sha ...

, had a Torsen differential. Rover Group fitted Torsen type 1, and later type 2, units to their range of high performance, front-wheel drive turbocharged models (220, 420, 620ti, and 800 Vitesse). The use of the Torsen differential was preferred by Rover Group; it is much better at controlling wheel spin in front-wheel drive vehicles than electronic systems which reduce engine power and therefore performance. The

Humvee The High Mobility Multipurpose Wheeled Vehicle (HMMWV; colloquial: Humvee) is a family of Military light utility vehicle, light, four-wheel drive Military vehicle#Military trucks, military trucks and utility vehicles produced by AM General. It ...

uses two Torsens, front and rear, with a normal manually lockable center differential (NVG242HD AMG transfer case) in the center. Other users of the Torsen limited-slip differential include the

Toyota GT86 The Toyota 86 and the Subaru BRZ are 2+2 (car body style), 2+2 sports cars jointly developed by Toyota and Subaru, manufactured at Subaru's Gunma assembly plant. The 2+2 fastback coupé has a naturally aspirated boxer engine, Front-engine, rea ...

and the Subaru BRZ, both released in 2012. The first Ford company vehicle to use a Torsen differential was the 2002 Ford Ranger FX4 (renamed in FX4 Level II from 2003) all of which used T-2R in the rear differential only. Starting in 2012, the Ford F-150 SVT Raptor uses a front Torsen differential and the Ford Mustang Boss 302 uses a rear Torsen differential. AMG offered Torsen differentials as an option as early as 1988 for new as well as for retrofitting for 107, 116, 123, 126 series Mercedes Benz cars. Toyota Altezza (sold in Europe, the U.S. and Canada as Lexus IS200 and IS300) came with a Torsen differential. For Lexus models it was included with all IS300 models with manual transmission and with the IS200 Sport, and was optionally factory equipped with automatic transmission. The Toyota Altezza was standard on all manual transmission SXE10 models (with the 5th-generation Beams 3S-GE engine and J160 6-speed manual transmission).

Torsen applications

Center

Q4 versions: 156 Crosswagon & Sportwagon, 159, Brera & Spider Q4 * Quattro versions of

: ** Audi Quattro (1987-current) ** Audi 80 & 90, Audi S2,

Audi RS2 Avant The Audi RS 2 Avant is a high-performance version of the Audi 80 Avant estate car, manufactured from March 1994 to July 1995. ETKA official factory data Collaboratively designed as a joint venture between Audi AG and Porsche and based on Audi' ...

** Audi 100 / Audi 200 / Audi 5000 ** Audi Coupé quattro **

, Audi S4, Audi RS4 ** Audi A5, Audi S5, Audi RS5 ** Audi A6, Audi S6, Audi RS6 ** Audi A7, Audi S7, Audi RS7 **

Audi A8 The Audi A8 is a full-size luxury vehicle, luxury sedan (car), sedan manufactured and marketed by the German automaker Audi since 1994. Succeeding the Audi V8, and now in its fourth generation, the A8 has been offered with either front-wheel dri ...

, Audi S8 ** Audi allroad quattro ** Audi Q5, Audi SQ5 ** Audi Q7, Audi SQ7 ** Audi Q8, Audi SQ8, Audi RSQ8 ** Audi V8 (manual transmission) * Chevrolet TrailBlazer SS * Lexus GS, Lexus GX, LS 600h / LS 600h L, LX,

Lexus IS The is a compact executive car ( D-segment in Europe) sold by Lexus, a luxury division of Toyota, since 1998. The IS was originally sold under the nameplate in Japan from 1998 until 2005 (the word ''Altezza'' is Italian for 'height' or 'high ...

Mitsubishi Triton The Mitsubishi Triton or Mitsubishi L200 is a mid-size pickup truck produced by Mitsubishi Motors. In Japan, where it has only been sold intermittently and in small numbers, it was originally known as the Mitsubishi Forte and from 1991 as the ...

5th Generation *

Aero *

: 4Runner (All 4WD 4Runner from 2003-2009) and 4Runner Limited (2010 to present), FJ Cruiser 6-speed manual, Toyota Landcruiser 200, Toyota Landcruiser 120/150, Toyota Fortuner, Toyota Land Cruiser Prado,

Toyota Sequoia The Toyota Sequoia is a full-size SUV manufactured by Toyota mainly for the North American market since 2000 for the 2001 model year, being derived from the Toyota Tundra, Tundra pickup truck. It is the second largest SUV ever produced under th ...

Volkswagen Volkswagen (VW; )English: , . is a German automotive industry, automobile manufacturer based in Wolfsburg, Lower Saxony, Germany. Established in 1937 by German Labour Front, The German Labour Front, it was revitalized into the global brand it ...

: Passat (badged as 4motion) (B5 platform), Amarok (permanent 4motion version only), Touareg (2011 to present, without offroad package)

Center and rear

* Audi V8 with manual transmission

Front and rear axles

* Mitsubishi Pajero Evolution * Toyota GR Yaris

Front axle only

* Honda/Acura Integra Type R *

: GT, 147 Q2 * Honda Civic Si (2006-current) *

Honda Civic The is a series of automobiles manufactured by Honda since 1972. , the Civic is positioned between the Honda Fit/Honda City, City and Honda Accord in Honda's global passenger car line-up. The first-generation Civic was introduced in July 1972 ...

1.8 VTi Europe & UK (5-door & Aerodeck Wagon, 1996–2000) * Ford Focus RS *

Mitsubishi Pajero The Further information on the Mitsubishi P ...

* Nissan Maxima SE 6 Speed manual * Nissan Sentra SE-R Spec-V * Oldsmobile Calais W41 (7 cars equipped from the factory, C41 option code) * Oldsmobile Achieva W41 (7-10 cars equipped from the factory, C41 option code) * Rover 200 Coupe Turbo, 200 BRM/LE, 220 Turbo, 420 Turbo, 620 Ti, 820 Vitesse (200PS version only) *

Honda Accord The , also known as the in Japan and China for certain generations, is a series of automobiles manufactured by Honda since 1976, best known for its four-door sedan variant, which has been one of the best-selling cars in the United States sinc ...

Type R * Subaru Impreza STI (2005-current) * Ford F-150 SVT Raptor (2012-current) * Ford Super Duty Tremor (2020-current) * Renault Megane RS * Peugeot RCZ R * Peugeot 208 GTI by Peugeot Sport * Peugeot 308 GTI by Peugeot Sport

Rear axle only

* AMG retro-fitted and optional for: 107, 116, 123, 126 Mercedes cars * Audi V8 with automatic transmission * Audi R8 *

: 155 Q4, 164 Q4 *

BMW Z3 The BMW Z3 is a range of two-seater sports cars which was produced from 1995 to 2002. The body styles of the range are: * 2-door roadster (automobile), roadster (E36/7 model code) * 2-door coupé (E36/8 model code) The Z3 was based on the BMW 3 ...

* Citroën BX 4x4 with ABS (same as Peugeot 405 4x4) * Dodge/Ram Heavy Duty Equipped with 11.5 AAM Rear Axle (2003-current) * Ford Ranger FX4 2002 only, Ranger FX4 Level II (2003-2009) *

* Hyundai Genesis Coupe * Lancia Delta Integrale *

, Lexus IS F,

Lexus LC The is a grand tourer manufactured by Lexus, a luxury division of Toyota. Based on the 2012 Lexus LF-LC, LF-LC Concept, it was revealed at the North American International Auto Show#2016, 2016 North American International Auto Show in Detroit. ...

, Lexus LFA, Lexus RC F, Lexus GS F, Lexus LS 460 F Sport trim * Maserati Biturbo *

Mazda is a Japanese Multinational corporation, multinational automotive manufacturer headquartered in Fuchū, Hiroshima (town), Fuchū, Hiroshima Prefecture, Hiroshima, Japan. The company was founded on January 30, 1920, as Toyo Cork Kogyo Co., Ltd. ...

Miata/MX-5 (option on 1994-2005 manual transmission models) *

RX-7 FD3S *

RX-8 *

Nissan is a Japanese multinational Automotive industry, automobile manufacturer headquartered in Yokohama, Kanagawa, Japan. The company sells its vehicles under the ''Nissan'' and ''Infiniti'' brands, and formerly the ''Datsun'' brand, with in-house ...

Silvia S15 SpecR *

Skyline R34 GTT, 25GT-X, 25GT-V Manual *

4x4 with ABS (same as Citroën BX 4x4) *

Peugeot 505 The Peugeot 505 is a large family car produced by the French manufacturer Peugeot from 1979 to 1992 in Sochaux, France. It was also manufactured in various other countries including Argentina (by Sevel from 1981 to 1995), China, Thailand, Indon ...

turbo sedan (1989 only) * Subaru Impreza WRX STI (2007–current) * Toyota Caldina ST215-W only *

Toyota Celica GT-Four The Toyota Celica GT-Four is a high performance model of the Toyota Celica, Celica Liftback that was produced from 1986 to 1999, with a Turbocharger, turbocharged ''Toyota S engine#3S-GTE, 3S-GTE'' engine, and full-time Four-wheel drive, AWD. I ...

, Toyota Supra, Toyota Soarer, Toyota Aristo, Toyota Mark II,

Toyota Chaser The is a mid-size car produced by Toyota. In the beginning, Chasers were four-door sedans and hardtop sedans; a two-door coupé was available only for the first generation. It was introduced on the Toyota Mark II (X30) platform and was only avai ...

Toyota Cresta The is a mid-size luxury car built by Toyota. It was launched in 1980 and shared the chassis with the Toyota Mark II, Mark II/Cressida and Toyota Chaser, Chaser and was the top-level car at Japanese dealership ''Toyota Vista Store''. The ...

, Toyota Verossa,

Toyota Altezza The is a compact executive car ( D-segment in Europe) sold by Lexus, a luxury division of Toyota, since 1998. The IS was originally sold under the nameplate in Japan from 1998 until 2005 (the word ''Altezza'' is Italian for 'height' or 'high ...

Toyota RAV4 The is a compact crossover SUV produced by the Japanese automobile manufacturer Toyota. It is known for starting the wave of compact crossovers. The RAV4 is one of the best-selling SUVs of all time. By February 2020, a total of 10 million RAV4 ...

, Toyota MR2 Spyder, Limited, Toyota GR Yaris *

4th Generation (1999-2002) *

4th Generation (1999-2002) *Chevrolet Camaro SS, Pontiac Firehawk & Comp T/A 4th Generation (optional in 1996-1997) *Subaru Legacy Spec. B (2007-2009 in US market) * 2012 and 2013 Ford Mustang Boss 302, option. Standard on Laguna Seca Edition. * 2014 Ford Mustang Shelby GT500, option. * 2014 Ford Mustang GT, included in GT Track Package. * 2015-2017 Ford Mustang GT, included in Performance Package. *

(also sold as the Subaru BRZ and Scion FR-S in various markets) *Ford F-450/500 Super Duty (1999-current) *Ford Explorer Timberline (2022-2024)

References

{{reflist

External links

3D Animation of a Torsen DifferentialTorsen Traction official site

Torsen traction control article
(PDF)
Popular Science articleArticle from 1915 about the Muehl differential, a similar device
Automotive transmission technologies Automotive technology tradenames Audi