Transmission & Drivetrain

The 4L80E may be an old transmission from General Motors, but it has been revamped with the latest and greatest modern parts to boost its performance. As a result, performance enthusiasts may not think twice before settling for this old transmission.

Several remanufacturing companies are continually developing parts to work alongside the transmission and bring out its best functionality. We’ll be taking a look at these parts and generally, what makes the 4L80E the right choice out of a range of transmissions that were also launched in the 90s.

 

4L80E Transmissions 101

The 4L80 is a series of automatic transmissions designed by General Motors. The nomenclature stands for a 4-speed transmission, longitudinally-mounted, and for handling GVWR (Gross Vehicle Weight Rating) up to 8000 lb. Thus, the 4L80-E is an automatic transmission, and it featured four forward gears and was tailored for longitudinal engine configurations.

Upon its launch in 1991, the 4L80E was used in vans, Chevrolet/GMC pickups, commercial vehicles, and the Hummer H1. It was later adopted in the Rolls Royce in 1991, and after extensive testing, it was also used in the Bentley Continental R and other Rolls Royce, Aston Martin, Jaguar, and Bentley vehicles.

Generally, the 4L80E is an evolution of the Turbo-Hydramatic 400 automatic transmission. Why is that? It featured the 400 parts and strength; however, it came with a lockup torque converter, added overdrive gear, and advanced electronic controls.

 

Application of the 4L80E

The 4L80E found application in several vehicles for 22 years before it was replaced in 2013. That length of usage and its popularity can largely be attributed to its improved fuel consumption as a result of its overdrive gear, ability to handle more torque, its durability, amongst other benefits.

Before this time, the transmission was meant to be used in the duty range of 4L60E and the Allison series transmissions. Allison transmissions were employed at the time in medium-duty class (4000 series) trucks. For this reason, the 4L80E was mostly resorted to, and it was available with the Big Block 7400 gas and 6.2L / 6.5L diesel.

Despite the advantages the 4L80E had over its predecessors, it still came with its problems such as losing the reverse gear and experiencing hard shifts. Nonetheless, the latest parts have been designed with seeks to handle these problems.

 

4L80E Performance Parts and Upgrades

Upgrades to the 4L80E have been made possible with the use of the following high-end components from different manufacturers of hardware devices. These parts include:

 

1. Pistol-Grip Shifter for 4-Speed Transmissions

The GM four-speed automatic transmissions with forward-shifting valve bodies such as the TH700R4, 4L60E, and 4L80E transmissions can feature a quarter stick shifter. The shifter also comes with a detent activation to curb missed shifts, neutral safety switch, and an NHRA- and IHRA-compliant reverse lock-out.

Similarly, the pistol grip shifter is CNC-machined from billet aluminum that has been anodized black, and it comes with replaceable side plates. Within this shifter’s installation kit are components such as a 5-foot, heavy-duty shifter cable, hardware, a mounting bracket, and an instructions manual to makes its installation a breeze.

 

2. An Independent Transmission Controller

A car enthusiast who intends to upgrade to any of the GM transmissions including the 4L60/65/80/85E can take advantage of a stand-alone transmission controller. What this controller does is to enable users to adjust shift points and feel. Adjustments can also be made to the torque-converter lockup using the supplied touchscreen controller.

Over and above that, adjustments enable accommodation for the gear-ratio, and changes to the tire-diameter. On the other hand, the controller comes as a kit featuring the touchscreen display, output for a speedometer, windshield mount for the display, and complete wiring harness.

 

3. GT Sport Chassis for 1963-1967 Corvettes

The need for a memorable ride while driving a classic car like the Chevrolet Corvette Sting Ray can be attained without suffering the limitation of the car’s original architectural design. The latter is made possible with an AME GT Sport Chassis that helps to improve the ride’s quality, handling of their rides, and its stance.

For instance, AME’s Multi-Link independent rear suspension system with a Sport IFS upfront is used to replace the car’s rear suspension. Also, the overall track width is slightly narrower compared to that of the factory-made, which is in a bid to provide wider wheel fitment and lower ride height.

On the other hand, the gusseted and triangulated frame has 0.180-inch-wall-thickness frame rails, and it is paired with exhaust passages that have been built into the crossmember.

 

4. Classic Mopar Gauges

Classic Mopar Gauges that still maintain the factory resemblance can be used in a car featuring the 4L80E transmission. Like the factory gauges, the red, white, and blue Mopar logo radiates on the black dial underneath the needle’s pivot. Some companies have taken it one step further to ensure that these gauges have been officially licensed by Mopar.

As such, if you’re a purist bent on finding a set of gauges that are close to factory-made ones to ensure efficient performance, this would be it.  What do these gauges offer? You may wonder! They provide full electric movements that are backed by several hours of track-tested accuracy.

Similarly, the gauges you can find are oil pressure, fuel level, water temperature, and a voltmeter in 2-1/16-inch diameter. There are also a programmable speedometer and tachometer in a 3-3/8-inch diameter.

 

The Bottom Line

Each of these components is evidence that the 4L80E transmission can be built with the latest and greatest parts to improve its performance. The ability to do so has prevented this transmission along with other GM four-speed transmissions from going into extinction.

On a timely basis, different manufacturers of hardware are constantly developing parts to handle their performance and even take it one step further. That being the case, settling for the 4L80E transmission in the current year would still be a good choice given the performance upgrades and the revamped components in the market that can be used on it.

Thus, it is now left for you to decide which manufacturer can give you the part you desire and has built it to be durable and handle all the power that will be put on it.

Whether your transmission rebuild is working perfectly today, or it is already giving you problems, great thought has to be given to its dyno-testing because only a few companies go through the dyno-testing process.

Here’s what we’re getting at, it is essential to know if your transmission rebuild was dyno-tested for internal pressures and leaks, hydraulic, and system controls. The aim is to ensure it stands the test of time and does not break down when you least expect.

Re-manufacturers or transmission rebuild shops, for instance, will either give you a guarantee or assurance of a dyno test, but it is easy to confuse one with the other as an accurate measure of quality. While a guarantee says a cost-effective solution for your car needs was provided, a dyno test comes with a promise that the gearbox will not fail unexpectedly before reaching its full life expectancy.

This is because the transmission has been tested under operational conditions to ensure it has been built to work properly, reliably, and give you life expectancy. But more about that later!

What Is a Transmission Rebuild?

A transmission rebuild are those that have been dissembled entirely in a bid to replace its worn and damaged parts with new ones. The rebuilding process also involves the inspection of parts for possible wear occurring in the future. A transmission component that may be vulnerable is then replaced with a better part.

For this reason, a transmission rebuild offers the guarantee of quality, unlike a used transmission. They are also faster to find than a used transmission.

What Is Dyno Testing?

A dynamometer (dyno) testing is the use of specially-designed equipment to examine the state and operation of a transmission system if it meets factory pressure specifications at operating temperatures. The hours-long process is carried out by mounting a transmission on the dynamometer and applying a rotational force and other external forces on the transmission.

On the same note, if you’re bent on knowing an engine’s horsepower, then all it’ll take is to connect it to a dyno. Here, the dyno places a load on the engine and then measures the amount of power produced by the engine against the load.

Minor repairs can also be carried out while the dyno is on the machine. Other checks that can be carried out include:

• • Stall speed
  • Converter lockup
  • Transmission line pressure
  • Shift point and response downshift

Components of a Dyno Machine

A transmission dyno machine consists of a powerful electric motor, pressure gauges, and mountings, internal combustion motor, as well as computerized operator panel and readouts. The pressure gauge, for instance, helps to monitor the pressure readings in the transmission.

Setup of this nature measures the force, the moment of force (torque), and pressure of the transmission, and it can be explicitly used on transmissions whose mountings and measurements are specific to a transmission drive.

Similarly, the test simulates a real operating environment by examining the gearbox’s speed and gear changes, design speed range in each gear, among others.

Verification of a Transmission Dyno Testing

A dyno testing proves that the transmission’s gearbox is operating according to factory specifications within its full design speed and gear range. The latter can be assured since the test measures the transmission’s pressure, force, torque, temperature, and efficiency.

In the same vein, a technician carries out a post-operational check on the bolt torque and leaks. That being the case, a dyno test allows the transmission to undergo several operational conditions and measures the output of all each state.

Can Transmissions Fail a Dyno Test?

Most certainly, not all transmissions pass the dyno test due to several conditions. In a situation where the transmission does not perform under factory specifications, then it will not pass the dyno testing. When that happens, the transmission will be stripped down and rebuilt while it is in high gear in a bid to ensure it passes the dyno-test.

It is, however, not a bad thing that it failed the dyno-test since it informs that there is a need for an improvement which could see a more revamped transmission rebuild. That being the case, you can reap the full benefits of quality transmission rebuild, which is known to be reliable.

What If Your Transmission Is Your Business?

If you’re a transmission rebuild shop or company in the remanufacturing industry, you’ll agree that reputation matters, and it begins by giving your customers quality gearboxes. How else can you assure them that the transmission you’ve handed over to them won’t fail in operating conditions?

It is through dyno testing that will check if the transmission will fail under these conditions. A dyno test will also check the transmission’s quality thoroughly to ensure that it does not fail or potentially cause more damage to the engine.

Nonetheless, bypassing this step either to cut costs or time can negatively impact your reputation in the long run. And that could be bad for business given the return that will be made, the potential for a ruined reputation, and the extra work that will have to be put into the transmission rebuild.

How to Ensure a Quality Transmission Rebuilt?

A quality remanufactured gearbox designed by professionals is one that does not only come with a guarantee, but it has been dyno tested. If it passes the test, then it could even be better than a new transmission due to its high quality.

The Bottom Line

Now that you know why it is important for your transmission to be dyno tested, it can help you to determine if the faults prevalent in your vehicle emanated from the low-quality transmission.

In the same vein, you’re aware at this point that not only is a guarantee necessary, but a dyno testing since it takes it one step further to assure you that the gearbox has been tested to meet factory guidelines.

When each of these is in place, you can have a high-quality transmission that can stand the test of time and the full functionality of other components it is paired with. For businesses, it will save your brand’s name and help spread the word that a reliable remanufacturer is in town.

You may be torn between the decision of whether it is worth replacing or rebuilding a transmission. It may also become an important decision to make, especially if you need to get your car back on the road after its transmission has failed. However, there are several tips on buying high performance transmissions online, whether it is used or remanufactured. These tips will ensure that the rebuilder you settle for is one that saves you money in the long run.

Tips on Buying Performance Transmissions Online

There are several offers online for transmissions, which can make it a bit difficult to make a decision of which to settle. It’s even more challenging given the number of promises they all come with, and as such, you have to rely on the word of the manufacturer and the honest reviews of previous buyers.

Nonetheless, spotting a good performance transmission can be easier than you imagine by considering the following tips when buying a high performance transmission online.

1. Rely on a Local Transmission Rebuild Shop

Before heading online to search for the best performance transmission out there, your best bet would be to take a closer look at the local rebuild shop that offers a good warranty. Local shops come with a lot of benefits, and one of such is the promise of better service when its time to fall back on the warranty.

Let’s face it, while a small percentage of transmissions fail, there is still the potential for your used or rebuilt transmission to develop faults at some point. When a fault occurs when you’d least expected, a warranty becomes beneficial.

A local shop would be in a better position to fix it since the hassle to get it checked is less. Unlike an online store or out-of-state rebuilder, it would require repackaging and shipping it off just to get it checked.

2. Non-Rebuilt or Used Transmissions Are Cleaner Than Rebuilt Transmissions

When it comes to buying a performance transmission online, you need to consider if a used or rebuilt transmission is what you want. Before you make a choice, check this out!

Automakers design transmissions in clean environments, and for this reason, the fluid in a new transmission has fewer contaminants. It also means that a used low-mileage transmission from a trusted auto parts dealer or auto-recycler is cleaner and a cheaper alternative than an expensive built performance transmission that may have been opened on more than one occasion.

For instance, performance aftermarket companies that rebuild transmissions may not carry out the operation in clean environments. Also, the steps involved in tearing apart your transmission’s core and rebuilding it with replacement parts may be carried in an environment of this kind.

The result has been proven in a study that shows that for each time a transmission is opened and rebuilt, the fluid has higher contaminants than an Original Equipment (OE) manufactured transmissions.

Specifically, the test showed that such fluid could be 5 to 103 times dirtier (presence of contaminants), which could be higher depending on the transmission’s model. It’s worth noting that a transmission’s fluid is vital because it allows the power to be transferred from the engine to the pavement.

Thus, if the fluid is contaminated, it could cause bushing failure, burned clutches, worn valves, worn gears, accumulator wear, rubber seal, amongst other undesired effects. Contamination can be prevented in rebuilt transmissions by using more filters than what can be found in the OE transmission because once it is opened, it will be dirtier. In addition, you need to form the habit of checking the transmission fluid to see if there are any indication of problems.

3. Inexpensive Deal from a Local Transmission Shop/Rebuilder

Who doesn’t like return and loyal customers? Local transmission shops or rebuilders most certainly do. And that is why they may put in their best in rebuilding a transmission that can offer power and speed.

In the same vein, they are bound to offer you a sweeter deal compared to what you may find online. Look at it this way; they believe that if they do an excellent job at yours and for a good price, then there’s a high chance you’ll refer them to family, friends, colleagues, etc. There’s also the warranty benefits of sending the transmission out the door if it gives you any hassle.

An online seller, on the other hand, may already have hundreds of orders and would be trying its best to meet deadlines. In a rush, a lot can go wrong, and that would be at the expense of a transmission you are paying heavily for.

4. Prioritize Common Failure Points of the Transmission Family

It is quite easy to be carried away with horsepower and torque ratings, which is why online companies parade these terms as an accurate measure of a bulletproof transmission.

However, it is a marketing scheme because these are not the actual horsepower and torque ratings that the transmission can handle. An accurate measure can be ascertained after a reliable or valid test has been carried out to know if the horsepower and torque ratings specified are on par with what the transmission can handle.

On the contrary, the latter may not be so because not every transmission gets tested in a vehicle – because the cost and time of removing and replacing the transmission in each engine would finally take a toll on the company.

Online re-sellers also parade with the same notion that these transmissions have been dyno-tested or road-tested when in actuality, they haven’t. The big idea is, a good number of performance transmissions ship untested and there is no standard for testing transmissions, at the moment.

To that effect, resort to a local rebuilder who will fix the common failure points and also give you the warranty that it will stand the test of time within a specified period.

5. The Hype of Performance Aftermarket Companies

Performance aftermarket companies need to sell their built transmissions and if that means hyping what it can do a little, no problem. But what happens when it’s at your expense, then a lot can go wrong.

On the contrary, you need to be realistic and know what is possible even when you are promised a 700HP. It is not going to handle 700HP, even though it says so.

Look at it this way, GM an original equipment manufacturer may have spent millions on building the 4L60E and transmission family. Such a transmission may have been tailored to operate to its full potential at a particular horsepower and torque rating.

Performance aftermarket companies, on the other hand, will work on the same transmission which millions of dollars have been showered on its design, but in this case, change a few parts with low-quality hardware.

Also, not all parts are changed, which means that they have not all been toughened to handle 700 HP. In the end, what you get is a transmission where specific common failure points have been handled but without offering 700 horsepower from a 350 horsepower.

6. Check Out Customers’ Reviews and Recommendations

If you’re bent on buying a performance transmission online, you will do well to go through the hundreds of customer reviews and recommendations. You’ll be able to judge if the transmission’s specs have been hyped or if it can deliver high performance in real-life.

Your ability to know between either of these lies in the honest review of happy and displeased customers. The hard truth is, most online aftermarket performance transmission is based on hype and not facts.

Thus, you should know if the transmission can give you a performance equivalent to money’s worth, something close to it, or you’re better off staying away from it in the first place. Nonetheless, these reviews can be attributed to certain factors:

• • The level abuse the transmission will be susceptible to and if it is powerful enough to withstand.
  • How the transmission has been built to be bulletproof based on the specifications that have been outlined, and in some cases, it has not been built to meet what has been stated.
  • Sending the customer a used transmission that has been repainted instead of one that has been rebuilt to improve its performance.
  • The customer’s unrealistic expectations and sometimes based on the hype they have been led to believe.

These aside, some online and offline rebuild shops are more than willing to give you a list of customers they have sold used transmissions to. You could obtain the list and make findings for yourself if these customers were satisfied with the results they achieved.

Conclusion

These are the tips on buying high performance transmissions online, which will enable you to choose from a wide range of options.

Whether it’s a local rebuild shop or online aftermarket company you’ll settle with for a custom high performance transmission, you can look over the hype and know the real-life performance to expect from the rebuilt transmission.

In the end, it should be a transmission that can deliver an acceptable level of performance.

Modern cars have become more complicated from what they were before due to the launch of new technologies. These technologies have led to features such as dual-clutch, CVT’s, semi-automatic, and automatic transmissions, transmissions built with as high as ten gears, among many others.

Unlike manual transmissions that can disconnect the engine from the transmission using a clutch, the same cannot be said for automatic transmissions. The reason is, automatics are devoid of clutches and instead, rely on the torque converter to keep the engine turning while the gears and wheels in the transmission come to a halt.

Thus, the torque converter in cars with automatic transmissions is very important in any vehicle today and if your transmission is blown or you’re experiencing symptoms of a blown transmission, then the culprit could be its converter as we’ll soon take a look at.

What Is a Torque Converter?

A torque converter is a coupling that helps in the transfer of power or torque from the car’s engine to its transmission. Also, this coupling relies on fluid hydrodynamic in a bid to enable an independent spinning of the engine without the help of the transmission. For instance, an idling engine when a driver gets to a stoplight reduces the torque that is passing through the torque converter.

However, this amount of torque is still enough to require pressure on the brake to stop the car from creeping. More power or torque is then transmitted to the wheels when engine’s speed increases and more fluid is pumped into the torque converter as a result of the brake being released, and the gas is stepped on.

Basics of Torque Converters

As already stated above, the torque converter enables power or torque to be transmitted from the engine to the transmission. The torque converter consists of three parts, and these are the impeller, turbine, and stator. Let’s take a closer look at each:

1. Impeller

The impeller or pump is the first significant component of a torque converter. This unit contains fluid, and it spins simultaneously with the engine’s crankshaft. As the impeller spins faster, more force is exerted on the fluid, which enables it to flow through it quicker and harder.

2. Turbine

The next assembly of blades within the torque converter is the turbine, and it is located opposite the impeller. On the other hand, the force exerted by the impeller causes fluid to flow into the turbine, and the latter begins to rotate as the fluid touches its blades.

It is worthy to note that this fluid is moved from the outer part of the turbine to its inner part repeatedly before it is finally transferred to the impeller. This constant movement of fluid from the impeller to the turbine and back to the impeller helps to create a fluid coupling. Also, the cycle of spins between the impeller and turbine helps to create torque.

However, the fluid flows in the opposite direction compared to when it was transferred from the impeller. As a result, this brings about the need for the direction to be reversed and that can be made possible using the stator.

3. Stator

A stator is a set of blades that are located between the turbines on the transmission shaft. The stator blades are positioned at angles that will enable a fluid’s direction to be reversed once it flows through it, and then be resent to the impeller.

A reversal in direction will slow down the fluid while increasing its torque. Also, when the car halts, the one-way clutch of the stator allows it to stop spinning, which stops the hydrodynamic circuit.

Root Cause of a Blown Transmission

A blown transmission can largely be attributed to torque converter problems which should not come as a surprise given how important this unit is in your car. The good thing is, getting a replacement for your torque converter is quite easy even though the bone of contention is being able to spot where the problem is emanating from.

Nonetheless, this should not be something to worry about since the outlined below will give you an idea of the potential issues in your car that can cause your transmission to blow up, leading to expensive repairs. Some of these signs that you need your transmission checked include:

1. Overheating

Overheating is never a good thing for your car since it is the first obvious sign that the transmission fluid is low and torque converter problems. That being the case, it can cause the torque converter to overheat and prevent it from transferring torque from the engine to the car’s transmission.

You’ll know it’s the effect is gradually taking a toll when you experience poor acceleration. On the long run, overheating of the torque converter can lead to a degradation of the transmission.

2. Shaking and Shuddering

Your car is meant to move smoothly and swiftly; however, if it begins to shake and shudder, it calls for serious attention. You can quickly tell when you’re driving on a smooth road, and it still feels like you are stepping on small bumps.

What could be the problem at this point? The shaking and shuddering could be as a malfunctioning in the lockup clutch. That being the case, you need to check that your lockup clutch is not worn out to eliminate any difficulties in moving from acceleration to direct drive.

3. Slipping

Another torque converter problem that could affect your seamless driving is its damaged fin or bearing. Slipping can also be as a result of too much or insufficient fluid in your transmission.

When this happens, there could be delays in transmission shifting it the transmission could slip in and out of gears. These problems can mostly be linked to the inability of the engine torque to be converted efficiently to hydraulic pressure required to shift gears within the transmission.

Conclusion

Advancements in technologies may have led to new features in automatic transmissions; nonetheless, the torque converter has always been an active part of these cars to enable the transfer of torque. That is why a car problem you’re experiencing now, especially a failure in your transmission can be pinned on the converter.

Possible signs such as overheating, shaking, slippage, among others is a dead giveaway that your converter needs to be checked. Consequently, it’ll save you the time, effort, and money, of trying to discover what the issue could be while you spend more time trying to resolve it in the best possible way.

The advent of several transmissions since the launch of automobiles means there are a whole lot of them in 2019 and many more can be expected in years to come. However, some like the Mopar 727, which is known for its strength and easy adaptability in just about any car makes it essential to understand how to identify Mopar 727 performance transmissions. It is needful given the many characteristics and advantages that can still be derived from using a transmission that is three decades old.

The Mopar 727 is also an excellent transmission to install into your Chrysler, AMC, or GM car or truck; thus, it can serve Chrysler and non-Chrysler applications. That being the case, we’ve outlined the unique physical and operational features of the Mopar 727, which will enable you to differentiate it from a wide range of transmissions that are also contending for attention.

What Is the Mopar 727 Performance Transmission?

The Chrysler A-727 transmission, also known as the TorqueFlite 8 units is a three-speed transmission that was launched around 1956. It was mainly used in Mopar cars with larger engine size from 1962 and also found a use case in certain vehicles as their original equipment component.

The A-727 transmission is robust and highly adaptable in several applications which can be attributed to its widespread use in about 30 years. Its strength meant it could be used in Chrysler cars and non-Mopar applications such as work trucks as well as high-performance vehicles like sports cars.

Within these vehicles, the Mopar 727 could handle engines whose horsepower went as high as 450hp which was an attestation of its strength. It can also work well in higher torque or higher rpm, and most notably, cars in which a bulletproof automatic transmission is required.

To that effect, if you decide to use this transmission today, then it will begin with knowing how to identify a Mopar 727 performance transmission.

Easy Ways to Identify 727 Performance Transmissions

Upon the launch of the earliest version of the A-727 in 1956, it featured a cast-iron case. However, from 1962, there was a switch to the use of aluminum cases. Thus, you’ll find one of the latest A-727 transmission using an aluminum case just like the Mopar vehicles between 1962 to the late 1980s. The A-727 is also unique from its oddly shaped oil pan with 14 bolts.

Other features that will enable you to identify the Moper 727 performance transmission are:

1. Transmission Bands and Shift Ratios

There are two transmission bands on the A-727 where one band serves for reverse and the other for kick down. This transmission’s shift ratios were:

• • First gear: 2.54:1
  • Second gear: 1.45:1
  • Third gear: 1.0:1
  • Reverse gear: 2.21:1

2. Adoption

A lookout for when the release year of the Mopar vehicle can help you ascertain if it is using an A-727 transmission or not. For instance, Mopar vehicles between 1962 and the late 1980s began to use the aluminum-cased A-727. The aluminum-cased A-727 was adopted in performance vehicles from other manufacturers from the mid-1960s. Similarly, the Jensen Interceptor and its Chrysler 383 engine took advantage of the Torque Command “8” which was released in 1956 as its automatic transmission.

3. Bell Housing

Depending on the engine you want to install the A-727 transmission in, it is needful to get one whose dimension or bell housing is right for your vehicle. An 18-inch bell-housing bolt pattern was used by small-block V-8s while an 18.875-inch bolt pattern was used by Chevrolet big-block applications. The AMC V-8 engines were drilled to the right small-block bell housing bolt pattern, and their rear output shaft can be a perfect fit to existing Jeep transfer case assemblies.

4. Transmission Upgrades

There were several upgrades to the A-727s which makes it needful to select the correct year of the donor car whose transmission you’ll be installing in your vehicle. That being the case, A-727s were push button shift whose push buttons were located on the dash from 1962 to 1964.

Few units from 1965 were still cable activated, but a majority of transmissions from 1965 and newer ones have a rod-style shift linkage. Between 1962 to 1965, transmissions featured a rear flange instead of a yoke linked to the driveshaft with a universal joint. Transmissions from years above this range featured a standard splined shaft using a basic slip yoke and cross-type U-joints.

5. Flexplate

Minor changes were still made to the A-727 after 1966, and one of such was the modification in flexplates in 1968 as well as the inclusion of a lockup converter in 1978. It is, therefore, important to select the right flexplate since those from 1968 and after came with flexplates with a larger center hole compared to those before 1968. In the same vein, a torque converter from 1966 and years after that, will not interchange into torque converters from years before 1966.

6. Year

An A-727 can also be identified as being a 1978 and newer lockup units just by examining the transmission’s input shaft. It was built with a lockup if the shaft is smooth at its last half inch, on the contrary, if it is splined to the end of the input shaft, then it is a non-lockup transmission. Pre-lockup converters before 1978 are also weighted as A, B, and C weights, and there’s no need to interchange either of these when trying to select the correct torque converter.

Conclusion

After taking a look at the easy ways to identify a Mopar 727 performance transmission, choosing the right one to install in your vehicle becomes a breeze. The A-727 is worth it when consideration is given to the fact that it’s been over 30 years since its first release; however, it can still offer strength and support high-performance power.

Whether its a replacement you’re looking for your Chrysler, AMC, or GM car, the A-727 is easy to find. All it’ll take is to tell it apart from a wide range of transmissions in the market using the specifications we have outlined above.

What’s more, selecting an A-727 that is right for the application it will be used in, takes it the extra step to ensure the level of performance you get is an impressive one. Thus, it is entirely up to you to make a choice from several depending on the year they were made whether they are older or newer versions of the Mopar A-727.

Ford’s C4 and C6 3 speed automatic transmissions are similar in operational characteristics; however, there are still unique differences between the C4 and C6 transmissions. Starting from the year they were produced, their specifications, as well as their applications, these two transmissions are worth comparing side by side.

For instance, while C4 transmissions may have been launched and further designed in different versions between 1964 and 1981, C6 transmissions found application in certain vehicles around 1966 to 1996. The list goes on and on, but there are also similarities between these two and the most obvious is that they are automatic transmissions that change gears automatically unlike manuals.

Nonetheless, let’s take a closer look at the differences between Ford C4 and C6 transmissions.

Differences Between Ford C4 and C6 Transmissions

The Ford C4 and C6 transmission specs show that there are apparent differences between either of these. The peculiar disparity between both include:

• • Year of production
  • Weight
  • Internal components
  • Evolved versions
  • Fluid type

1. Year of Production

The Ford C4 is also called the Dual-Range Cruise-O-Matic, FMX transmission and it was produced around 1964 and was used until 1981. Specifically, the vehicles that came with a C4 transmission were the Ford Bronco between 1973 to 1977, and the Ford F-series between 1965 to 1981. Here’s what it looks like:

• • Ford Bronco (1973–1977)
  • Ford Cortina (1974–1982 )
  • Ford F-Series (1965–1983)
  • Ford Fairlane (1964–1970)
  • Ford Fairmont (1978–1983)
  • Ford Falcon (1965–1970)
  • Ford Granada (1975–1982)
  • Ford LTD (1975–1980)

The C6 automatic transmission, on the contrary, was launched by Ford around 1966 and it found use cases until 1996. It was produced at Ford’s Livonia Transmission Plant, Michigan and in the mid-1980s, its production was transferred to a Sharonville Transmission Plant, Ohio.

Also, the C6 transmission was used in high-performance vehicles as well as trucks with more significant engines such as Ford trucks, passenger cars, and Lincoln cars. The C6 was evident in the Ford F-Series between 1967 to 1996 as well as the Ford Bronco between 1978 to 1991. In the latter version, five bell housings were used, and these are:

• • Diesel bell housing.
  • FE bell housing for the Ford FE family engines.
  • The Cleveland bell housing in the 351M, 400, and Ford 385 engine family.
  • Windsor bell housing for all Windsor engines, 300 “Big Six” I-6, and the 351 Cleveland.
  • Mel 462 used in 1966 to 1968 462 V-8 Lincoln Continental as well as 1968 to 1970 460 V-8 Lincoln Continental.

2. Weight

Ford C4 is a medium-duty transmission judging from its lightweight of 130 lbs dry w/ torque converter and its design with an aluminum case. So, if you’re wondering how heavy is a C4 transmission, then it does not pack so much load at all.

On the other hand, C6 transmission is a heavy-duty transmission that can handle much load. Like its predecessor, it featured a lightweight at 175 lbs dry w/ converter and an aluminum case. It is believed that by today’s standards, a transmission of this nature has a high-level parasitic loss as a result of its weight and size.

3. Internal Components

The C4 can be split into three sections, which are the transmission case, bell housing, and the tail housing.

On the other hand, the C6 identification is the Borg-Warner flexible shift band and the Simpson planetary gearset it features. Within its case are a one-piece casting and a bell housing.

Upon the C6’s launch, it featured 17.4 inches, 7 inches, and 14 inches tailshaft housing lengths for the Lincoln cars, Ford trucks, and Ford passenger cars, respectively.

4. Evolving

A look back at the C4 and C6 transmissions when they were launched shows that there have been other variants since then. An instance is the case of the C4, which featured a 0.788 inch, 24 spline input shaft between 1964 to 1969.

However, upgrades to the C4 in 1979 brought about a 26 spline, 0.839-inch shaft. The same was evident in 1971 when the input shaft was updated to feature 24 splines at the clutch hub and 26 splines on the torque converter side.

5. Fluid Type

Transmission fluid is essential in a car to allow the components to move swiftly while at the same time, ensure there is no overheating or slippage. Accordingly, the kind of transmission fluid the C4 uses is the Type F automatic transmission fluid. In contrast, the transmission fluid supported by the C6 is the Type FA automatic transmission fluid.

6. Modern Use

The contemporary use of the C4 and C6 transmissions are for different purposes. While both are used by hot rod and drag racers enthusiasts, the C6 has gained favoritism when it comes to offroad driving. The C4 is not quite suitable for off-road since it cannot handle as much power as the C6 and as such, it was mostly used in cars and not trucks.

7. Gear Ratios

The C4 gear ratios are:

• • First Gear 46:1
  • Second Gear 46:1
  • Third Gear 00:1
  • Reverse Gear 20:1

The C6 Gear ratios are:

• • First 46:1
  • Second 46:1
  • Third 00:1
  • Reverse 00:1

Similarities Between the Ford C4 and C6 Transmission

While there is a significant disparity between the C4 and C6 transmission, it’s worth noting that there are slight similarities between both. Some of these include:

• • Transmission speed
  • Simplicity
  • Upgrades
  • Gearset
  • Aftermarket support

1. Transmission Speed

The C4 and C6 are both 3-speed automatic transmissions designed by Ford.

2. Simplicity

Both transmissions’ design spoke simplicity and durability. The C6, for instance, was admirable for its simplicity, strength, and reliability. It is even more durable than the C4, which makes it more expensive. As of today, it is still a popular choice for motorsports such as off-road and drag racing vehicles.

3. Upgrades

The C4 and C6 transmissions later had better versions of themselves and what was also noticeable between the duo is that they then featured an overdrive gear.

Thus, if you’re wondering if a C4 transmission has an overdrive, it most certainly does today. The overdriven gears were not present when they have launched as well as a lockup torque converters which are now evident in new transmission for boosting fuel economy.

Similarly, the response to questions like how many gears does a C6 transmission has, would be three. What this boils down to, is earlier versions of these transmissions are entirely different from their later iterations.

4. Gearset

The C4 and C6 transmission upon their launch both depended on a Simpson planetary gearset.

5. Aftermarket Support

Given that it has been decades since the launch of the C4 and C6, a car enthusiast can get excellent aftermarket support for both transmissions.What’s also worthy to note, is that they have been revised to handle torque better than their older versions.

How to Tell a C4 From a C6 Transmission

A closer inspection of the C4 and C6 shows a similarity in physical appearance. However, they can be told apart by considering the following:

• • Determine the number of bolts securing the transmission’s oil pan to the transmission itself. On the C4, there will be 11 bolts while on a C6, there will be 17.
  • Ascertain where the drain plug is situated at the transmission pan. If the plug is at the side of the transmission’s pan, it is the C6 but on the bottom means it’s a C4.
  • Determine where the speedometer driver gear is located. If it is on the driver’s side of the extension housing, it is the C6 but a C4, if it is at the rear of the transmission at the point, then driveshaft is connected to the transmission’s back.

Conclusion

Judging from the internal and external components, there are apparent differences between the C4 and C6 transmissions. These differences will enable you to tell a C4 from a C6 transmission despite their similar appearance. There have also been upgrades to either of these two in order to improve their level of performance from what they could offer as at when launched.

Nonetheless, in the present year and beyond, they’ll still be noteworthy as some of the most popular transmission ever designed by Ford Motors. Their performance also has led to the creation of modern automatic transmissions which car fanatics have come greatly to rely upon.

There are simple, yet effective ways to build the perfect automatic overdrive (AOD) transmission through the use of off-the-shelf components and aftermarket kits.

That may come as a surprise since the AOD was not intended to serve as a performance transmission given that Ford Motor Company had begun fitting them in a bunch of Lincoln Town Cars, and vans.

However, then came the AOD-E, an electronically controlled transmission instead of the cable-modulated AOD which car enthusiasts had so many issues with.

AOD-E was not the last member in the series because the 4R70W was later launched.

Thus, between 1980 and 1991, there were upgrades in the AOD family which makes the AOD today more than ready to be boosted for a higher level of performance. So, whether it’s the AOD, AOD-E, or 4R70W, they are all hardy transmissions that could still use some level of improvement in order to attain fuel economy and performance.

Let’s take a quick look.

The Advent of AOD Transmissions

AODs were launched by Ford around 1980s as a new transmission generation.

AOD, the first member of the family is a mechanically-modulated transmission featuring a throttle-valve cable (TV) whose role is to modulate shift timing, shift firmness, and line pressure.

Asides from the AOD, the AOD-E and 4R70W were later launched and the duo are quite similar in their mode of operation. This is because both transmissions are electronically controlled and as such, they do not have a TV cable which makes the engine and transmission operate cohesively.

AOD Transmission Types

The later AOD types may be electrically controlled, but there is still a notable difference between the AOD-E and 4R70W transmission. What sets either apart is their gear ratio.

The 4R70W as an improved version of the AOD-E comes with better gearing which can significantly increase the acceleration of a small or big-block Ford.

Similarly, the transmission has been specially tailored for the 4.6L Modular V-8 (Ford Modular engine) and as such, it eliminates the snappy low-end torque in a small- or big-block Ford.

Limitations of the AOD Transmission

It doesn’t come as a surprise that the AOD came with its own bone of contention. Some of these limitations were:

1. Not Wide-Enough Overdrive Band

The AOD transmission has a 1.50-inch-wide Overdrive band as well as a Reverse clutch drum which could break down under strain and may not fit securely.

These were maintained until the launch of the ’93 Lincoln Mark VIII which showed a major improvement given that it featured a wider 2.0-inch Overdrive band and Reverse clutch drum.

2.  Pecky TV Cable

Asides this, another limitation was a throttle-valve (TV) cable function that was evident in the AOD upon its launch.

Let’s take the TV cable, for instance, it had to be adjusted on the spot using a pressure gauge with a test drive and intuitive feel that it’s time to shift in order to prevent burning up the transmission. The TV cable’s build was connected to the throttle movement which determined the line pressure depending on the throttle position.

3. Split-Torque

In the same vein, the split-torque 60/40 function works with a secondary input shaft which is removable but linked to the torque converter’s shell and forward clutch.

There’s another shaft which serves are the primary input shaft and works with the torque converter’s turbine in First, Second and Reverse gears.

The engine’s torque, in this case, has been split since 40 percent is passed to the torque converter while the remaining 60 is passed to the smaller input shaft in Third gear.

Building the Perfect AOD

It is entirely possible to build the perfect AOD transmission just by changing some of its internal components and using aftermarket kits. Envision the AOD as a core that needs to be filled with the right parts to boost its performance.

But first, you need to be on the lookout for AODs that were launched towards the end of the 1980s since these ones came with an improvement in their internal gear-train.

As a result, the teething problems in early AODs were combated unlike in the past where they were handled using revised gear-train and valve body parts.

Now consider the following when trying to make your AOD better:

1. Choose the Right Aftermarket Parts

The right aftermarket parts will greatly determine the level of performance you get after building the AOD transmission. When done right, your transmission can take as high as 800 horsepower (hp) and even 1200 hp in some cases which translates into a dependable and rugged AOD.

It begins with your choice of the AOD-E or 4R70W geartrain which feature a wider Reverse drum and Overdrive band. These are able to handle the load that will be put on them even better.

You can take it one step further if you settle for the 4R70W since it can accelerate faster due to its better gearing. A durable 4340 chrome-moly input shaft should also be used since it can eliminate the input shaft breakage problems evident in stock shafts.

In the same vein, the “A” Overdrive servo should be selected in order to achieve greater Overdrive band clamping pressure.

2. Throttle Valve Cable Adjustment

The TV cable can either be adjusted using a pressure gauge or without one. Nonetheless, it is highly recommended to use the pressure gauge.

The pressure gauge should also be screwed into the line pressure port which is situated at the right-hand side of the transmission case.

If you’ve properly screwed the pressure gauge, then there should be a  0-5  Pounds per Square inch (psi) at idle speed, 30 psi at normal acceleration, and 85 psi of line pressure at wide-open throttle. When the speed is idle, it is expected that there should be no tension but slack tension on the TV cable.

On the other hand, if you had resorted not to use a pressure gauge for the installation, the cable tension should also not be slack.

As such, applying the shifter in gear should bring about a gentle engagement instead of a jolt. A test drive is necessary at this point starting with light acceleration and then a hard acceleration.

A light one should result in a firm upshift with an increase in speed while a hard one should produce firm but delayed shifts.

On the contrary, cable tension needs to be increased if slippage occurs in order to prevent the transmission from overheating and getting burnt.

3. Proper Installation of the Torque Converter

When it comes to the installation of an AOD, great care and attention have to be given to the torque converter installation.

The torque converter must be properly installed on the primary and secondary shafts, stator support and front pump rotor in order to prevent front pump damage and failure. Ensure that there are three moments that enable the converter to pop to the next position.

You can tell that the converter has been rightly placed when your hand can’t get between the bell housing and the converter.

4. AOD Adaptor and Conversion Kits

There are several AOD transmission adaptor kits for Ford applications.

Their purpose is to enable you to install an AOD transmission in your chosen vintage Mustang vehicle other than the 170ci and 200ci inline-sixes. AOD conversion kits also make it easier to install a Ford AOD in your vintage mustang. These kits will ensure that you get an efficient overdrive mounted in your ride in no time.

The AOD conversion kit, for instance, is packaged with TV cable, trans mount, 164-tooth flexplate, slip yoke, adjustable manual-shift linkage, and installation hardware.

Conclusion

You too can build the perfect AOD transmission today and it all begins with choosing between the AOD-E or 4R70W as an AOD core. There’s also the need to carefully select the right internal components since they will significantly contribute to the performance of your vintage machine.

Similarly, these installations will only be made possible with the use of AOD adaptor and installation kits which make your work much easier and result more productive.