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The Ford AOD and 4R70W Transmission History and Evolution is on Baumann Electronic.

The postwar years gave time to forget about the Great Depression.Fuel was plentiful after World War II and we became wasteful.Gas wars were common.It was quite common prior to World War II, but it faded away due to cheap and plentiful gasoline and low-buck engine repairs.

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The Arab Oil Embargo was a rude awakening for spoiled American motorists.Large-displacement V-8s, heavy automobiles, and 2- and 3-speed straight-drive automatics came with a price at the pump.It was a great ride when fuel was cheap and plentiful.Our ultimate fate would be higher fuel prices.Increased fuel-economy standards were imposed by the federal government when the second oil cri-sis arrived in 1979.Detroit was ready with more fuel efficient automatics.Ford was no exception.

The Automatic Overdrive entered service in full-size Fords, Mercurys and Lincolns in 1980.The AOD's geartrain is borrowed from the older, time-proven MX, FX, and FMX transmission family.The internals were put in a fresh case with an overdrive unit.

The Ford C5 was an updated version of the venerable C4.In the late 1970s, Chrysler did the same thing with its Torqueflite with a locking converter andLean Burn electronic engine/powertrain control system.General GM joined the crowd with its cars.

The first domestic automatic overdrive trans-mission was introduced by Ford in 1980.General GM and Chrysler followed.The 904 and 727 were added to Chrysler's 3-speed automatics.The 200 was further developed into a 200-4R with a purpose-built automatic overdrive.

There are add-on hydro-mechanicals and direct overdrive lockup to eliminate wasteful slippage in older C4 and C6 automatics.

Ford's all-new AOD in full-size Fords, Mercurys and Lincolns was a fresh design, yet it incorporated existing tried-and-proven Ravigneaux geartrain components borrowed from the BorgWarner FMX parts bin.The AOD is reliable thanks to the use of time-proven components.It took quite a few years for Ford to get the AOD dialed in to be a solid performer, however, and this occurred with help from the aftermarket and off-road racers.There were problems with the AOD's overdrive unit, which was a new design.The problem was solved by the 1993 Lincoln Mark VIII AOD Electronic Control.

The AOD passenger's side has dipstick tube access, cooler line connections, and pressure ports.The AOD has two bands with an accumulator at the rear, as you can see from the case design.There are three things from left to right in the case.Pull the pan and valve body to access them.The AOD is limited because of its bellhousing.The FE-series big-block, Y- Block, Bronco, older F-Series, and more are available for the AOD.

The driver's side of the AOD shows the linear multi-pin connector backup light and neutral safety switch, the manual shift lever, and the dogleg TV cable connection.The TV cable linkage is connected to the bell-housing threaded boss.

There are two ports for the dipstick tube and cooler line.The AOD dipstick tube clears most firewalls on classic vehicles such as the Mustang, Cougar, Fairlane, Torino, F-Series trucks, and Broncos.If stock tubes won't, the aftermarket dipstick tubes are for those vehicles.

The bellhousing of the AOD is designed for large blocks and small blocks.Installation of the AOD is difficult.It is seated on the two input shafts and the front pump drive.Damage and transmission failure can be expected if it isn't fully seated.

The AOD has two input shafts, a large hollow main input shaft and a smaller solid overdrive/torque conversion lockup shaft, which are more for light-duty cruising once you get up to speed.The largest shaft is not rotating.

The small solid overdrive/locking converter input shaft transfers power to the overdrive unit in lockup only.It's important to get the torque converter seated on the main input shaft, as well as the smaller lockup shaft.The front pump drive rotor must be fully seat into the converter.It is all done by feeling.

The old-school, tried-and-proven durable geartrain of the AOD is borrowed from BorgWarner.The work of two planetaries is done by the Ravigneaux gearset.

The AOD has a stamped-steel pan with the words "Automatic Overdrive" and "Metric" on it.The AOD pan is shaped differently than the AODE pan.

The AOD has been an outstanding transmission for street and strip use for more than 30 years.Vintage Ford enthusiasts love the simplicity of the AOD and the variety of installation kits available in the aftermarket.California Pony Cars has everything you need to swap the AOD into a classic mustang.Performance automotive transmission center has a variety of AOD and 5R55 swap kits and parts.There are swap kits for the Ford flathead V-8.Another source is the Bronco grave-yard.Several sources allow you to put the AOD behind a big block.

The AOD is a true hydromechanical 4-speed automatic transmission.The TV cable, tied to the vehicle's throttle linkage, works like a kickdown linkage but it is more finite in its execution because it does the work of both a downshift linkage and vacuum modulator used on earlier Ford automatics.The only TV cable with the AOD is the older C3 and C4 transmissions.

The C3, C4, C6, and FMX transmissions have vacuum modulators that can be used to control shift-points.The kickdown linkage works with the vacuum modulator to control shift points for wide-open throttle downshift.The line pressure is finitely controlled by the vacuum modulator.At WOT, the kickdown delivers maximum line pressure.The vacuum modulator is eliminated by relying on the TV cable to control shift-points.The TV cable needs to be adjusted properly.Proper adjustment can lead to transmission failure if it is not done by the book.

The AOD has a gearset that wraps around the sun gear and shell.The center support is a stamped assembly.

Load is distributed across a broad surface area by the compound planetary gearset.The benefits of two gearset in one is that it offers some weight reduction and engineering simplicity.

The AOD has a main input shaft, reverse clutch drum, forward clutch, and direct clutch cylinder.This is how they fit into the transmission case.

The main input shaft drives the AOD's forward clutch assembly.The direct clutch is on the bench.

The AOD has a cast-iron and steel gear pump.The intermediate clutch piston is located behind the pump and holds the forwardmost clutch pack.

The AOD has a front pump case casting number.There are variations in the casting number of this pump depending on when it was cast.

There is a difference between a standard AOD reverse drum and a 1993-up Lincoln AODE/4R70W reverse/overdrive drum.Increased surface/friction area causes the Lincoln reverse drum and overdrive band to hold better.The wider reverse drum/overdrive band is what you want for an AOD build because of its greater holding power and reduced chance of failure.The wider band should never be used without the wider drum.

The valve body of the AOD did not change much during its production life.The AODE/4R70W valve body has computer control, but its throttle valve function is different.

When the part was produced, look for the Ford casting number on the main cases and valve bodies.The AOD RF-E0AP-7A092-AF valve body is from 1980.

There is an engineering revision time frame of 1989.Rouge Foundry is thought to mean RF.

The AOD tailshaft housing has a 1980 original casting on it.The part of the casting number that says "E0AP" doesn't always mean it was cast in 1980.The number 25 indicates which sand-cast mold the piece was cast from.In mass production, sand-casting cavities were used on cast-iron or aluminum parts.Casting issues can be found with the help of Cavity numbers.The bellhousing has a number on it.

The multi-pin backup light/neutral safety switch is only for AOD.The linear switch is operated by a cam inside the case.It forbids starting in any drive gear range and illuminates the backup lights in reverse.

On the backup light/neutral safety switch, the copper pin rides a manual shift cam linkage that moves the pin in a linear fashion to open the circuit.Late Model Restorations has this switch.The multi-pin plug is available from Ron Francis Wiring.

The AOD is an old-school automatic with hydromechanical function and a conventional tailshaft flyweight valve governor.Control pressure and shift-points are affected by it.If you have purchased an AOD core of unknown origin, there are variations that you need to be aware of.

The disassembled AOD governor shows function.There is a plug, sleeve, spring, and retainer clip from left to right.The complete assembly is shown, but the valve assembly and counter-weights are not.The governor valve is spring loaded and works against both load and force.As the output shaft spins faster with vehicle speed, the valve piston overcomes spring pressure and line pressure goes to work.This affects shift points.It affects both upshift and downshift points.You get a higher shift-point if you use a stiffer spring.Spring pressure is used to calibrate.

The AOD has a clutch pack and a low reverse band.There are also two one-way clutches.There is a dual pin-ion set that provides four forward gears and one reverse in the geartrain.The AOD is a tough competitor in the world of automatic overdrive transmissions.

Because most AOD transmissions have the six-bolt bellhousing design first introduced in 1965, they fit behind any large or small engine.Smaller bellhousing V-8s do not bolt to the AOD.You can bolt the AOD, AODE, and 4R70W to big-block Ford V-8s with aftermarket adaptor kits.The AOD has become one of the most trusted automatics.

The Ford Blue Oval stamped into its 14-bolt galvanized steel pan is the easiest way to identify the AOD.The AOD is similar to the C6 in that it is a one-piece casting that includes bellhousing and main case.The AOD has a screw-in multi-pin linear connector backup light/neutral safety switch on the left-hand side above the manual shift and TV cable linkage.

There are three fine-thread bolts and a 10-mm sockets in the AOD.The filter should never be cleaned again.During a fluid change, always replace it.

This is the AOD manual shift mechanism with the valve body removed.The throttle valve shaft is inside the manual valve detent.Both have seals that need to be replaced.The Lokar aftermarket external linkage is used in this application.

The AOD valve body is visible with the removal.The overdrive band, low-reverse, and 3-4 shift accumulator can be found from left to right.In 1989 a revised valve body and plate was added to the 3-4 shift accumulator.The 3-4 shift accumulator is required if you use a 1980–1988 AOD valve body.

The AOD main case has the accumulator covers and pistons removed.Ford eliminated the accumulator in production, so some AOD cores are not equipped.The 3-4 shift accumulator was phased out due to leak issues.The separator plate on the valve body has been revised to accommodate this production change.Don't worry if your AOD does not have a 3-4 shift accumulator.

The main transmission case mates with the AOD valve body, which has a manual shift valve and shift modulation valve.There are two basic ways in which the manual shift valve can be used.The TV cable adjustment affects the control pressure of the throttle valve.Upshifts occur exactly when they are supposed to, with optimum cable tension.Tension and upshifts come too early.Tension and upshifts come late.

The Lokar manual shift bell crank and TV cable were installed in a vintage F-Series truck.The manual shift points downward at 6 o'clock if you have a column shift.The Lokar TV cable is no longer on.

A big improvement in efficiency with the AOD is the use of needle bearings.The AOD geartrain has some thrust washers.

The AOD transmission is easy to fit into any Ford application.Thanks to the perseverance of the aftermarket, such as California Pony Cars, it has become easy to swap the AOD into a vintage Ford, Mercury, or Lincoln with a variety of installation kits.If you already have an AOD in your Ford, you will understand the benefits of this transmission.The key to getting along with the AOD is learning as much as possible about its function and how to properly execute a rebuild and tune.

The benefit of over-drive in the AOD is only one of the benefits.Lockup takes place inside the overdrive unit instead of the inner input shaft, which is what most automatic overdrives do.Non-slip direct drive is offered in fourth gear and third gear as well.

Torque multiplication and slippage can be achieved with a gentle throttle tip-in.You can get fuel efficient direct drive between the shell and output shaft if you relax the throttle.The split-torque occurs when the transmission comes out of the overdrive lockup and you are on the torque conversion.2 to 212 times your engine's Torque is achieved with Torque multiplication.

With the split-torque feature, Torque multiplication can be done with a straight drive and no slip-page at cruise.The difference between 70 mph and 2,500rpm is the AOD's efficiency.The overdrive lockup and straight drive off the torque converter give you a reduction in the RPM and corresponding efficiency.It makes a difference between 15 and 20 miles per gallon.There is a benefit to less wear and tear.

The AODE was introduced in 1991 to make engine and transmission function more cohesive.AOD Electronic Control delivers precision operation thanks to more unified engine and transmission electronic control.No TV cable adjustment, just a computer-controlled operation based on the factory settings.The AODE was conceived for a new generation of overhead-cam Modular V-8s that first arrived in the 1991 Lincoln Town Car.The AODE was installed behind the Ford pushrod V-8s.The pushrod small-blocks were given extra snap by the AODE.

The AOD is similar to the AODE, but there are important differences to be aware of before attempting a rebuild.Even though it shares the same architecture, the AODE is a different transmission.It has a different main case, valve body, and other vital components.The split-torque function in third and fourth gears was eliminated by Ford.

The AODE has a compound planetary gearset with two sun gears and a dual pinion set.Like the AOD, there are two bands, two one-way clutches, and four friction clutches.

The name AODE was used from 1991 to 1992.The 4R70W was introduced in 1993 behind the V-8 in the new Lincoln Mark VIII.It appeared in some F-Series trucks.

The AOD arrived in 1991 to improve performance and fuel economy.The AOD case for the AODE and 4R70W transmissions was designed for electronic interaction with engine controls.

The AODE and 4R70W are the same transmission.The 1997 4R70W has a speedometer drive and an output shaft speed sensor.The manual shift lever is visible.The backup light/neutral safety switch is missing.

The backup light/neutral safety switch is on the 4R70W transmission.The output shaft speed sensor is above the switch.The engine and transmission cohesiveness is unified by it.

The AODE/4R70W has an output-shaft speed sensor and plug on the driver's side.There is a backup light/neutral safety switch on the driver's side of the transmission.

The shift solenoid and lockup multiplex plug is on the passenger side of the AODE/4R70W.The connection eliminates the need for a TV cable.

The electronic speedometer drive sensor takes the place of a cable drive and mechanical speedometer.The AODE/4R70W output shaft housing still has a mechanical speedometer drive.

The tailshaft housing is for an AODE or 4R70W.The Basic Aluminum Casting Company in Cleveland, Ohio produced the tailshaft housing for the Ford Motor Company.There were at least 61 molds when the sand was cast.

The AODE and 4R70W have a larger input shaft.The AODE/4R70W has an input shaft instead of a primary and intermediate shaft.

The AOD has a linear backup light/neutral safety switch, but the AODE does not.The function is outside the case.The pressure control solenoid is large and heavy and is used to control system pressure.You could experience transmission damage if it malfunctioned.

The AOD is not interchangeable with the AODE valve body.The AOD has a throttle valve.The system pressure programming and shift-points are computer controlled.A bolt-on detent is used to lock shift positions.

The AODE had a raw wiring harness that connected the multiplex system plug to the shift control solenoids.The wire channel on the 4R70W has good security.Shift-control solenoids are the two side-by-side ones.The lone solenoid is for a lockup.The pressure control connection is at the far right.

The AODE and 4R70W have no tools for removal or installation.Before buttoning up, make sure the rubber seal and filter are secure.Don't reuse a filter.

There are Ford casting numbers on all of the castings.It's important to know which transmission you have and what parts should be used.

The AODE/4R70W transmission pan is unique to these units because it uses a different bolt pattern and a deeper sump for improved cooling and lubrication.

The AODE/4R70W planetary gearset uses an improved first-gear ratio for better acceleration.The AODE/4R70W gearset swaps into an AOD to get the better holeshot.

The AOD iron gear pump has the same pressures as the AODE front pump, but at a higher volume at low engine speeds.

The AOD can work with engine operation thanks to the AODE/4R70W multiplex plug connection.It uses electronics instead of a TV cable that can move out of adjustment.

There are two shaft sensors for input and output shafts in the updated 4R75W and 4 R75E.There is a different main case for the 4R75-series transmission.

The AOD uses a split-torque overdrive unit lockup feature, but the AODE and 4R70W use a locking Torque Conversion.Ford wanted to create a more cohesive engine and driveline pack-age by moving away from split Torque.With the AODE/4R70W, you don't have to switch from one input shaft to another because the converter clutch disengages while you're in overdrive.The AODE and 4R70W have one input shaft.The AODE and 4R70W have disengagement instead of over-drive lockup.

The AODE front pump has been improved for better flow and increased lubrication.AOD and AODE front pump rotors have different number of teeth.There is a lot of the AODE/4R70W front pump.The aluminum pump is not as durable as it could be.

The AODE/4R70W has a new-and-improved valve body with two computer-controlled solenoid packages.The AODE valve body is thicker according to Ford.The AODE valves are made of aluminum and have the same expansion properties as the valve body.

The lower gear ratios in first and second gears make the 4R70W different from the AODE.The 5.0L and 5.8L pushrod V-8s have the same Torque curve as a small-block, but the 4.6L doesn't.The AODE lowered its first-gear ratio in order to improve standing-start takeoffs.

The 4R70W has evolved to be an even better transmission with engineering refinements and computer control thanks to the use of input and output shaft sensors.

Shift control via the valve body is one of the improvements.Along with gearset improvements and a more durable drum, Torque capacity became better.The 4R75's ring gear has 24 tabs instead of 6 for the output shaft sensor for more precise shift control.

The input shaft sensor and an improved front pump were added to the 4R75W.As you drive, there is a refined vehicle speed sensor.There is additional programming in the PCM that can be used in drive-by-wire vehicles.

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The Ford AOD and 4R70W Transmission History and Evolution is on Baumann Electronic.

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