The AOD (automatic overdrive) is a four-speed

automatic transmission An automatic transmission (sometimes abbreviated to auto or AT) is a multi-speed transmission used in internal combustion engine-based motor vehicles that does not require any input from the driver to change forward gears under normal driving c ...

, with the 4th gear as

overdrive Overdrive may refer to: Organizations * OverDrive, Inc., a digital distributor of entertainment media ** OverDrive Media Console, a media player developed by OverDrive, Inc. * Overdrive PC, a subsidiary of Velocity Micro Technology * Overdrive ...

. Introduced in 1980, it was

Ford Ford commonly refers to: * Ford Motor Company, an automobile manufacturer founded by Henry Ford * Ford (crossing), a shallow crossing on a river Ford may also refer to: Ford Motor Company * Henry Ford, founder of the Ford Motor Company * Ford F ...

's first four-speed automatic overdrive transmission. The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, '60s, and '70s. The AOD replaced many of Ford's older transmissions such as the C4, C5, and light duty applications of the FMX.

History

In 1962 Ford began working on a new type of automatic transmission that would emphasize fuel economy and driveability. The new transmission was built around the

Ravigneaux planetary gearset The Ravigneaux gearset 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 ...

of the "X" transmissions. Where many transmissions had a fourth gear added on as an afterthought, Ford's new transmission was designed with a fourth gear integrated into the gearset. Because it was based on the "X" transmissions, its gear ratios from 1-3 were the same with the fourth being 0.67:1. The transmission featured a split-torque application for third gear as well as a lockup in the torque converter. The XT-LOD was initially abandoned in 1966 but design began again in 1974 as a result of rising gas prices. The project was shelved with a design that lacked a damper in the torque converter but after the project was revisited a damper ultimately made its way into the final design. The transmission was introduced when Ford started to downsize its full size line in 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. Applications: * 1980–1986 Ford LTD * 1980–1993

Ford Thunderbird The Ford Thunderbird (colloquially called the T-Bird) is a personal luxury car produced by Ford from model years 1955 until 1997 and 2002 until 2005 across 11 distinct generations. Introduced as a two-seat convertible, the Thunderbird was pro ...

* 1980–1993

Mercury Cougar Mercury Cougar is a nameplate applied to a diverse series of automobiles sold by the Mercury division of Ford from 1967 to 1997 and from 1999 to 2002. While the nameplate is most commonly associated with two-door coupes, at various times during ...

* 1984–1993

Ford Mustang The Ford Mustang is a series of American automobiles manufactured by Ford. In continuous production since 1964, the Mustang is currently the longest-produced Ford car nameplate. Currently in its sixth generation, it is the fifth-best selli ...

* 1980–1986

Mercury Marquis The Mercury Marquis is a model line of automobiles that was marketed by the Mercury division of Ford Motor Company from the 1967 to 1986 model years. Deriving its name from a French nobility title, the Marquis was introduced as a rebadged counte ...

* 1983–1993

Ford Econoline The Ford E-Series (also known as the Ford Econoline or Ford Club Wagon) is a range of full-size vans manufactured and marketed by the Ford Motor Company. Introduced for model year 1961 as the replacement for the Ford F-Series panel van, the E-Se ...

* 1983–1991

Ford LTD Crown Victoria The Ford LTD Crown Victoria is a line of full-size cars that was manufactured and marketed by Ford from the 1980 to 1991 model years. Deriving its name from the Ford Fairlane coupe of 1955–1956, the LTD Crown Victoria served as the flagship ...

* 1983–1992

Mercury Grand Marquis The Mercury Grand Marquis is an automobile that was sold by the Mercury division of Ford Motor Company from 1975 until 2011. From 1975 until 1982, it was the premium model of the Mercury Marquis line of full-size sedans, becoming a standalone mo ...

* 1982–1993

Ford Bronco The Ford Bronco is a model line of sport utility vehicles manufactured and marketed by Ford. The first SUV model developed by the company, five generations of the Bronco were sold from the 1966 to 1996 model years. A sixth generation of the mod ...

* 1981–1992

Lincoln Town Car The Lincoln Town Car is a model line of full-size luxury sedans that was marketed by the Lincoln division of the American automaker Ford Motor Company. Deriving its name from a limousine body style, Lincoln marketed the Town Car from 1981 to ...

* 1980–1987

Lincoln Continental The Lincoln Continental is a series of mid-sized and full-sized luxury cars produced by Lincoln, a division of the American automaker Ford Motor Company. The model line was introduced following the construction of a personal vehicle for Edse ...

* 1980–1983 Continental Mark VI * 1984–1985 Continental Mark VII * 1986–1992

Lincoln Mark VII Mark 7 is the seventh chapter of the Gospel of Mark in the New Testament of the Christian Bible. This chapter explores Jesus' relationships with both fellow Jews and Gentiles. Jesus speaks with the Pharisees and scribes, and then with his discipl ...

* 1992

Ford Crown Victoria The Ford Crown Victoria ("Crown Vic") is a full-size sedan that was marketed and manufactured by Ford. The successor to the Ford LTD Crown Victoria, two generations of the model line were produced from the 1992 to 2012 model years. The Ford ...

* 1980–1993

Ford F-Series The Ford F-Series is a series of light-duty trucks marketed and manufactured by Ford since the 1948 model year. Slotted above the Ford Ranger in the Ford truck model range, the F-Series is marketed as a range of full-sized pickup trucks. ...

Gear ratios

* First: 2.47:1 * Second: 1.47:1 * Third: 1.00:1 * Overdrive: 0.67:1 * Reverse: 2.00:1

AODE

The AOD was redesigned with electronic controls in 1992, becoming the AOD-E. It was mainly intended for the new

Modular Broadly speaking, modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a sy ...

V8 at first, but it was also adapted to the old AOD bell-housing for vehicles still powered by

pushrod A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) ...

engines. While the AOD and AOD-E are similar to each other (oil pans, casings, bell-housing, and internals), they are not interchangeable with each other because the AOD-E's shift points are controlled electronically from a combination of solenoids and the Powertrain Control Module (PCM) while the AOD's shift points are hydraulically controlled by a throttle valve rod. Applications: * 1992–1994

* 1992 and up

trucks and

E-Series E series may refer to: * BMC E-series engine, a series of automobile engines * Electronic E series of preferred numbers, a series of preferred values for electronic components such as resistors, capacitors, inductors, zener diodes * Entwicklung seri ...

vans * 1993–1994

* 1993–1994

* 1994–1995

4R70W

A revised version of the AOD-E Transmission was released in 1993 with the

Lincoln Mark VIII The Lincoln Mark VIII is a grand touring luxury coupe marketed by Lincoln from the 1993 to 1998 model years over a single generation, manufactured at Ford's Wixom Assembly Plant. Succeeding the Lincoln Mark VII, the Mark VIII shared underpinning ...

. Unlike the AOD-E, Reverse, 1st, and 2nd gear ratios in the 4R70-W are numerically higher, giving the transmission a better mechanical advantage and in turn, better take-off acceleration, better passing acceleration, slightly lower fuel consumption, and designed for better gearset strength; The 4th gear ratio in the 4R70-W is up 0.70:1 from 0.67:1. Although this may sound bad, fuel economy is slightly increased and downshifting is slightly decreased for less wear. On vehicles powered by the 5.4L V8, a stronger gearset is used than in normal duty 4R70Ws and Torque Converter stall speeds is also slightly lower because of the 5.4L’s increased low end torque opposed to the 4.6L. In 1998, due to durability concerns, the intermediate one-way roller clutch was replaced with a mechanical diode providing extra holding capacity and longer service. While there is some speculation that the 70 can be multiplied by 10 to indicate the pound-feet of torque this transmission is capable of handling, including torque converter multiplication, (i.e. 700 lb-ft of torque), there is no reliable source indicating this. In fact a Ford document stated that the 2003 "Expedition's 4R70W transmission is rated to handle up to 506 pound-feet of torque, which provides a large performance cushion beyond the peak torque rating of Expedition's largest available engine." It is more plausible that the number indicates the torque handling capability in N-m, as 506 lb-ft converts to 686 N-m which could be rounded to 700 N-m. The "70" may also refer to the transmission's torque capacity after torque converter multiplication which occurs at low rpm's when the torque converter is more "elastic". 4R70W indicates 4 gears, Rear wheel drive and Wider gear ratio compared to the AODE. The gear ratios are: * First: 2.84 :1 * Second: 1.55 :1 * Third: 1.00 :1 * Overdrive: 0.70 :1 * Reverse: 2.32 :1 Applications: ** 1993–1998

** 1993–2003

** 1994–1997

** 1995–2004

** 1996–2001

Ford Explorer The Ford Explorer is a range of SUVs manufactured by Ford Motor Company since the 1991 model year. The first four-door SUV produced by Ford, the Explorer was introduced as a replacement for the two-door Bronco II. Within the current Ford light ...

** 1993–2004

** 1994–1997

** 1995–2004

** 2003

Mercury Marauder The Mercury Marauder is an automobile nameplate that was used by three distinct full-size cars produced by the Mercury (automobile), Mercury division of Ford Motor Company. Deriving its name from the most powerful engines available to the Mercury ...

** 1997–2004

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** 1997–2001

Mercury Mountaineer The Mercury Mountaineer is a mid-size luxury sport utility vehicle (SUV) that was sold by Mercury from 1996 until 2010. Sharing many of its features with the Ford Explorer, the vehicles were virtually identical in terms of hardware. Externally, ...

** 1996–2004

** 2004–2005 Rover 75 V8

4R75W

In 2003, Ford revised the 4R70W transmission to include: A stronger ring gear that has 24 lugs (as opposed to 6) for the output shaft sensor to read off of, a revised torque converter, a revised front pump assembly, and a vehicle speed sensor (VSS) that complements the OSS to improve shift quality and efficiency. These improvements allowed the 4R75W to handle more power while being more efficient and economical. While not used on all 2003 model year vehicles, the 4R75W/E transmissions eventually replaced the 4R70W/E. Newer transmissions that are referred to as 4R70E or 4R75E have modifications that complement Fords switching to throttle by wire. The PCM was given a more powerful microprocessor and Ford added a turbine speed sensor to the transmission. This allows the PCM to know the speed of the input shaft after the torque converter which is used in combination with crankshaft speed to detect the amount of slipping going on in the torque converter. This information provides PCM with the basis for fully electronic shift scheduling which limits "hunting" and fine-tunes shift speed and feel. It lets the PCM know what the torque will be in the next gear so it can choose the shift points based on the vehicle's projected performance in the next gear. Coupled with the electronic throttle strategy, the transmission computes the output torque required to maintain the vehicle speed, and chooses the correct gear and converter state accordingly.

Modification

The most practical modification for the 4R70W is the J-mod. It involves modifying the valve body separator plate and gaskets as well as changing or removing accumulator springs to alter the shift timing of the transmission. While these modifications can be done to the 4R75W transmission, the results are not as dramatic, as some of the details of the J-Mod (bigger holes in the separator plate and gasket) were done to the transmission in its design. These modifications are specified by one of the Ford engineers who designed the transmission. It offers faster engagement, quicker shifting, smoother operation, and increased service life. All parts can be bought at Ford dealers for less than $60 including the fluid. A 20,000+ GVW cooler is highly recommended for all vehicles. Breakdown of the transmission fluid often results in "converter shudder" (feels like driving over rumble strips) where converter tries to maintain a steady slip rate during lock-up, but alternates between slipping and grabbing. Frequent fluid changes, especially when used for towing, are the single best method to prevent shudder. Shudder occurs because the torque converter never fully enters "lock-up", and ends up bouncing in and out of lock-up to slip. This causes the engine to flare up and then down again as the clutch cannot hold back the power of the engine.

4R7xx Usage

2002 :''4R70W used in all applications:'' :*

Ford E-Series The Ford E-Series (also known as the Ford Econoline or Ford Club Wagon) is a range of full-size vans manufactured and marketed by the Ford Motor Company. Introduced for model year 1961 as the replacement for the Ford F-Series panel van, the E-Se ...

2003 :''4R75W Used in'': :*

(GT and Mach 1) :''4R70W usage in trucks:'' :* 5.4 L V8 F-150,

, and

:* 4.6 L V8

Van, 4.2 L and 4.6 L F-150 :''4R70W usage in cars:'' :* 3.8 L V6

Ford Panther platform The Ford Panther platform was an automobile platform that was used by Ford Motor Company from the 1979 to 2012 model years. Following the downsizing of the General Motors B-bodies and C-bodies by two years, the Panther platform marked the end ...

Cars:

and

2004 :''4R75E used in:'' :* 5.4 L 3 Valve V8 F-150 :''4R70E used in:'' :*4.6 L V8 F-150(except F-150 Heritage) :''4R75W used in:'' :*

Ford Police Interceptor The Ford Police Interceptor is a range of automobiles manufactured by Ford. First used in 1992, the range consists of existing Ford models modified and sold for use as police cars and other car-based emergency vehicles. Though Ford has histori ...

(GT and Mach 1) :*5.4 L 2 Valve V8 Trucks

Van, and

:* Rover 75 V8 :''4R70W used in all other applications:'' :* 3.9 L V6

:* 4.6 L V8

Cars:

, and

:* 4.2 L V6 and 4.6 L/5.4 L V8 Ford F-150 Heritage 2005 :''4R75E used in 5.4 L 2 Valve and 3 Valve Trucks:'' :* F-150 :*

:''4R70W used in:'' :* F-150 Heritage (sold only in

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

) :''4R70E used in:'' :* 4.6 L V8

:* 4.6 L V8

Cars:

, and

:* 4.6 L V8 Ford F-150 except F-150 Heritage (sold only in Mexico) 2006 to 2008 :''4R70W used in:'' :* Ford F-150 Heritage (sold only in Mexico) :''4R75E used in all applications:'' :* 2006-2011

Cars:

, and

. :*2007-2008 4.2 L V6, 4.6 L V8, 2004-2008 5.4 L 3 Valve V8

except F-150 Heritage (sold only in Mexico) :*2006

:*2006-2013 4.6 L V8, 5.4 L V8

References

{{Reflist
LINCOLNSONLINE.COM
AOD

History

Gear ratios

AODE

4R70W

4R75W

Modification

4R7xx Usage

See also

References