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Monthly Archives

July 2019

Building the Perfect AOD Transmission

Building the Perfect AOD Transmission - Gearstar Performance

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.


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.

200-4R vs. 700R4 Transmissions: A Comparison

200-4R vs. 700R4 Transmissions: A Comparison - Gearstar Performance

200-4R vs. 700R4 transmissions are two four-speed automatics that are always compared side-by-side for their similarities, yet unique differences. They may have been released in the 1980s, but where one fails the other makes up for it. It’s also worthy to note that the 200-4R vs 700R4 strength has been improved from what they were a couple of years ago.

They have been beefed up in every possible way to be a better replacement to any car that uses the TH350, TH400, or generally, a muscle car. Fuel economy for which they were launched for has been up by 30 percent based on their real-life operation.

However, the same level of performance may not be evident if you rely on the stock transmissions of either even though they are not as common as they used to be. Now that’s out of the way, let’s take a look at either transmission specs, problems, and selling point.

The 200-4R Transmission

The 200-4R transmission is one among several other transmissions manufactured by General Motors, an American multinational corporation based in Detroit. The transmission was launched in 1981 for the year’s model car and it is the lesser of the duo overdrive transmissions that were launched around the same time.

So, what cars came with a 200-4R transmission, let’s take a quick look:

    • KZ
    • 442
    • CZ Monte SS
    • OZ Hurst Olds
    • BR Grand Nationa
    • CQ Chevy 5.0L H.O.

The 700R4 Transmission

The Turbo Hydra-Matic 700R4 transmission was also manufactured by General Motors (GM) in 1982. It is also one of the first overdrive automatic transmissions launched by GM. The 700R4 transmission cars at the time were not limited to Corvettes, Camaro, Chevrolet, and pickup trucks.

200-4R vs. 700R4 Similarities

The 200-4R vs 700R4 similarities include the following:

1. Release Period

The 200-4R and the 700R4 transmissions were both released in the 1980s. At the time, there was a high need for cars with fuel economy and as such, the duo became the answer to the growing need.

2. TV Cable

The 200-4R and 700R4 use a Throttle Valve (TV) Cable or detent cable instead of the kick down cable that controls the TH350 and TH400 transmissions.

What a TV Cable does is to serve as a primitive throttle position sensor enabling either transmission to maintain the best RPM (revolutions per minute) possible for fuel economy and peak performance. It also enables them to shift smoother which allows a driver to switch between gear ratios seamlessly.

Nonetheless, there is still a 200-4R and 7004R transmission problems which have been pointed out time again. One of such stems from their TV Cable which has been said to be a bit finicky, thereby causing them to shift too hard, early or later than expected.

3. Overdrive

An overdrive is reputably known as a transmission’s highest gear. It enables the transmission to operate at a low RPM at any given road speed and as a result, it uses fuel efficiently and operates more quietly on the highway.

How does this relate to the 200-4R and 700R4? They also feature overdrive gears and they were notably the first GM automatic transmissions to feature such.

Today’s 4L60E finds its rooting from the 700R4 and like the latter, it has a .70:1 overdrive gear and basic design. The 200-4R, on the other hand, features a ratio of .67:1 which is known to be more aggressive and allow the engine to move 3 percent slower down a highway.

200-4R vs. 700R4 Differences

There are also unique differences between the 200-4R and 700R4 transmissions and some of these include:

1. Appearance

Is there any way of telling the 200-4R transmission from the 700R4 from the outlook? Definitely! You will need to rely on their pan bolt count and pattern.

It could be a little tricky in the aspect of the pan bolt count since the 200-4R vs 700R4 have the same number of pan bolts which is 16. However, the pattern or angle of the pan bolts is a dead giveaway as to which is which.

First, you need to count all the pan angles and if it is a 6 angled, then its definitely a 200-4R. On the other hand, it is a 700R4 if it has is equivalent to a 4 angled square. It also has a bigger pan and longer tail-shaft length than the 200-4R

2. Gearing

One of the most notable differences between either is in their overdrive gear. The 200-4R transmission has a .67:1 which is considerably more aggressive than the 700R4’s .70:1 overdrive gear. An overdrive gear of this nature on the 200-4R is equivalent to a low RPM when one is driving down a highway. Here’s a more precise breakdown of the overdrive gear ratios of both transmissions:

First Gear

    • 200-4R: 2.74
    • 700R4: 3.06

Second Gear

    • 200-4R: 1.57
    • 700R4: 1.62

Third Gear

    • 200-4R: 1.00
    • 700R4: 1.00

Fourth Gear

    • 200-4R: 0.67
    • 700R4: 0.70

The data above shows that the 200-4R’s 2.74 first gear is closer to the TH350 2.52’s first gear and even closer than the 700R4 (3.06). There is also the length of 27 11/16″, the width of 19 1/8″, and 27 spline output shaft being shared by both the TH350 and 200-4R. As a consequence, the 200-4R  is a better replacement to the TH350 in comparison to the 700R4.

Which Transmission Is Better?

Which is the better option between the 200-4R vs the 700R4 transmission can be determined by a number of factors and these are:

1. Purpose of the Car

The first obvious reason is the purpose the car will be put to. Is it for drag racing or street ride? If it’s for drag, then you’re better off with 200-4R thanks to the closeness of its gear ratios. There are, however, two limitations to the 200-4R in this aspect.

You’ll have to shift it manually as you race if not the shift points will be low. It is also expensive to find one that has been well-built. On the other hand, street use can be optimized with the 700R4 and as such, you’ll need this type for a street-worthy vehicle.

2. Aftermarket Support

Consideration is also to be given to which is more common in order to ensure that you can easily find aftermarket support in case you run into issues with the transmission. That being so, the 700R4 would be a better pick since it meets the criteria above.

3. Strength

A comparison of the 700R4’s first and second gear shows that there is a big difference between them. This results in a larger RPM drop in the gears in comparison to the 200-4R. There is also the longer nature of the 700R4 which requires certain modifications in order to cross member and driveshaft.

Conversely, the 200-4R can be made to be stronger than the 700R4. It is, however, worthy to note that the 200-4R is popularly known as the weaker of the 200-4R/700R4 pair.


The 200-4R vs the 700R4 transmission comparisons show their strengths and weaknesses as well as their similarities and differences.

Despite this, they are still a great choice of transmission if one is looking to increase the MPG (Miles Per Gallon) and reduce the RPM as the vehicle moves down the highway. Your choice of which should be determined by the use you want to put it to.

Nonetheless, the 700R4 takes it the extra mile by ensuring that while you have aftermarket support, the transmission’s life is also prolonged.

Nag1 Transmissions: 5 Things to Be Conscious Of

Nag1 Transmissions: 5 Things to Be Conscious Of - Gearstar Performance

Are you driving a car that uses the W5A580 automatic transmission or do you intend to buy one? Then there are certain things to be conscious of when using a Nag1 (W5A580) transmission.

Good knowledge about them will ensure that your transmission stands the test of time and serves you longer than you’d ever expected. In the same vein, there is an optimized level of performance to look forward to and all of this is wrapped around knowing the highlights and limitations of the W5A580 automatic transmission.

First off….

What Is an Automatic Transmission?

An automatic transmission is also known as a self-shifting transmission, an n-speed automatic or an auto. It is a car whose gear changes automatically on its own. As a result, there is no need for the driver to do so manually as would’ve been the case if a manual transmission is used.

In comparison to other transmission systems, an auto also allows the internal combustion engine which is best suited to run at a high rotational speed. The advantages of an automatic transmission include:

    • Improved shift comfort
    • Reduce fuel consumption
    • Increased reliability and service life

What Does Nag1 Mean?

Nag1 stands for “New Automatic Gearbox Generation 1.”

It is a family of transmissions that makes use of different marketing names such as W5A300, W5A380, and W5A580. The initials for these names in the case of W5A580 can be broken into:

    • W: A transmission that takes advantage of a hydraulic converter
    • 5: Five forward gears
    • A: Automatic transmission
    • 580: The maximum input torque capacity represented in Newton Metres

What Is the Nag1 (W5A580) Transmission?

The Nag1 (W5A580) is a heavy-duty 5-speed overdrive automatic transmission system with a lockup clutch in the torque converter. It is also known as a 5G-TRONIC transmission thanks to its torque converter lockup, 2-speed for reverse, and ability to support almost 600 lb-ft of torque. The system was designed by Mercedes-Benz, a Germany-based automobile company found in 1926.

Mercedes-Benz was once a part of the Chrysler family of companies and as such, the W5A580 was used in a good number of Chrysler products such as the Hemi engine which features a Challenger, Magnum, and Charger. This transmission can also be found in Mercedez V12 engine as well as their AMG high-performance vehicles. The same can be said about supercharged Jaguar applications.

Nonetheless, when you compare the W5A580 with some modern transmissions, it may be equivalent to comparing a fax machine to modern-day computers. The big difference is, the former struggles with speed while the latter offers seamless performance.

Things to Be Conscious of With the W5A580 Transmission

Like any transmission, there are pros and cons to it and the same can be said about the W5A580 Transmission. Its advantages and limitations are also some of the things you need to be fully aware of and they include:

1. Potential for water to enter through the dipstick tube

There is the problem of water entering the W5A580 transmission directly from the dipstick tube. This is the tube that enables you to check your engine oil accurately.

On the other hand, the potential for water to enter through the tube is often triggered by a defective O-ring, whose defection can lead to fluid leakage from the transmission. A solution that can combat the problem is to replace the O-ring with a new, upgraded O-ring which can be done by getting the car in the air to work on it, and then actually replacing the O-ring.

2. Sensitivity to the quality of transmission fluid used

The W5A580 transmission is extremely sensitive to the transmission fluid that is used within it. Even when there are tiny droplets of water (0.005 percent) in the fluid, the possibility for the transmission to shudder is high.

Now if you’re experiencing this shuddering already, you know that the culprit is the quality of transmission fluid you’ve used. A possible solution is to change the fluid and replace the internal filter which could help to remove any impurities such as fine debris and water in the near future.

For the filter it can use, an aftermarket external transmission filter would do just fine since this type of filter is built to be used alongside the factory internal filter. They are installed in one of the transmissions cooler lines and take advantage of a similar filter element that is comparable to those used in cleaning the engine’s oil.

3. Torque converter clutch problem

Another problem of the W5A580 transmission is its torque converter not holding correctly. The issue has been reported severally, and it can either be caused by a faulty clutch within the torque converter, faulty solenoid, or fluid contamination of the transmission. Despite this, it is not a widespread problem that should keep you on your toes.

4. Overheating due to abuse

W5A580 are used in high-performance cars which sometimes gives car owners the confidence that nothing can go wrong if they abuse the transmission. On the contrary, this is not always the case since the transmission could overheat, and if it does, it could lead to long term problems. Excessive heat, for instance, can destroy your transmission.

Facts About the W5A580 Transmission

Here are some facts about the W5A580 transmission:

1. Built to last longer

The W5A580 transmission has been built to last longer if it is given proper care. However, if it fails, then you can opt for a re-manufactured transmission which can serve as a better replacement in comparison to a rebuilt one.

This is because a re-manufactured transmission will always feature better modifications and upgrades in a bid to make them last longer. There’s also the advantage of an extended warranty either of which cannot be found in a rebuilt transmission.

2. Torque management system

The W5A580 transmission uses a torque management system whose aim is to enable the transmission to shift more smoothly.

3. Drive recognition software

W5A580’s Error Correction Mode (ECM) is programmed with drive recognition software. The purpose of the software is to aid in the customization of shift points depending on how the car braking system is used and how the user engages the gas pedal.

4. Stout transmission

The W5A580 can shift quickly and its gear ratios are spread out. As such, those who drive 600+ hp cars that are powered with the Nag1 can move swiftly. Even by today standards, it can still be said that this transmission comes with aftermarket programming that enables lightning-fast shifts.


These and many more are some of the things to be conscious of when using the Nag1 (W5A580) transmission. Keeping these things in check can ensure that your car’s engine does not break down especially when you need it.

It’s quite simple when you think about it since it revolves around carrying out the basics such as ensuring that the transmission fluid is of good quality and free from debris or water. Likewise, you need to have a filter that will ensure that there are no traces of either of these because if that happens, it could pose problems in the long run.

Manual vs. Automatic Transmissions for Off-Road Activity

Manual vs. Automatic Transmissions: Off-Roading - Gearstar Performance

Your choice between manual vs automatic transmissions for off-road activity is dependent on a number of factors. Each has its advantages and disadvantages, making it difficult to ascertain if a manual is better and faster than automatic, or if it is the other way round.

Let’s face it!

Stick-shifts may have been decades old, but they are still strong contenders with automatic 4x4s, which does not come as a surprise since they were the first around the block with a promise of beefed up engine.

That is why till today, there are still cars being designed with a manual transmission in order to meet the heart desire of car fanatics or off-road enthusiasts who will rather handle their own gears than trust the car to do it for them.

Similarly, in the world of off-roaders, there is also a debate as to which is a better option once you’re off the pavement. You’ll find performance lovers argue on the side of over shift speeds and lap times.

On the contrary, smoothness, traction, and control will be the advantages pointed out by automatic 4x4s lovers. But let’s take a look at each transmission and what it offers.

Manual Transmissions

Manual transmissions are also known as a stick shift or manual gearbox. It is a type of transmission that relies on a clutch that needs to be engaged or disengaged using the foot pedal or hand lever. The clutch also helps to regulate the transfer of torque from the engine to the transmission. There’s also the gear selector that can be used with the hand or foot.

Cars That Use a Manual Transmission

Some of the best cars that use a manual transmission are:

    • 2019 Subaru BRZ
    • 2019 Fiat 500 Abarth
    • 2019 Porsche 911 GT3
    • 2019 Ford Mustang GT
    • 2019 Mazda MX-5 Miata
    • 2019 Honda Civic Type R
    • 2019 Chevrolet Corvette Z06
    • 2019 Ford Mustang Shelby GT350

Automatic Transmissions

Automatic transmissions can be called self-shifting transmissions or autos and as its name describes; it changes the gear ratios of a car automatically as it moves. This, therefore, takes away the need for the driver to do so manually.

Cars that Use an Automatic Transmission

Some of the best cars that use an automatic transmission are:

    • Tata Nexon
    • Toyota Yaris
    • Renault Kwid
    • Honda Amaze
    • Hyundai Verna
    • Maruti Suzuki Celerio
    • Maruti Suzuki Alto K10
    • Maruti Suzuki Vitara Brezza

What Is Off-Roading?

Off-roading is the process of riding a vehicle on roads or tracks whose surface is made of materials such as rocks, sand, gravel, mud, snow, river beds, etc. Leisure drives or competitions can be carried out on such unsurfaced roads using customized vehicles that have been specially built to handle the intensity.

Off-Road Manual vs. Automatic Transmission

There are off-roading differences between manuals and automatic 4x4s, which could pose the question of what’s more reliable between a manual and automatic.

But in the end, it depends on what you want and you’re out to get because each comes with a certain level of control.

Here’s what it looks like:

Manual Transmissions

Here are some reasons why a manual may be better for off-roading:

1. Knowing What to Expect

You always know what to expect with a manual since it allows for more controlled ascents and descents. In the same vein, there is a more direct engine braking and immediate on downhill stretches. There’s also the advantage of being able to select the right gear while on low-traction surfaces, which will eliminate wheelspin or dig your way out of snow or deep mud.

2. Manuals Are Fun

Now, where’s all the fun when the car is doing most of the work on your behalf? That’s definitely out the window, but with a manual, you can still have that knowing you were able to achieve a eliminate wheelspin all from your skills.

3. Manuals Handle Heat Better

This argument has arisen time and again and at some point, one may have to agree. It is the idea that manuals tend to handle heat better which is good for the car’s transmission in the long run.

The Downside of Manuals in Off-Roading

Manuals may provide more control while on ascents and descents, but they are not too good for lower-speed climbs or low-speed driving. Crawling usually requires that the car comes to a halt as the spotter tweaks the driver’s part.

However, crawling successfully with a manual means clutching in and then trying again to get started which could be bothersome

Automatic Transmissions

Here are some reasons why an auto may be better for off-roading:

1. Automatic Handles Most of the Work

Automatic off-road cars such as the Jeep Cherokee XJs do most of the work for you which allows you to concentrate on other aspects of off-roading. There’s no need to disturb yourself about how to operate the clutch and switch to just the right gear.

2. Ability to Start from the Top

One more thing to look forward to is the automatics’ ability to start from the top such as a hill. They are better at crawling from the top with a low speed which would’ve required you to slip the clutch in a manual.

3. Ability to Halt Completely

If you’re on a steep rocky ledge, there’s the advantage of using the automatic transmission since it will enable you to come to a complete halt. This is made possible without relying on the clutch, which is a huge benefit.

The Downside of Automatics in Off-Roading

While automatic transmissions are a better option for low-speed ascents, if you’re looking to climb the hill at a high speed or try sand dune driving, manuals would be a better choice. You can build speed while in a high gear at the base of the incline before shifting to a lower gear towards the top as momentum is lost.

It’s also worthy to note that heavy brake application is required while using autos for descents. The transmission may not allow a drive to lock into the first gear which brings about the possibility of the transmission switching into second gear while the drive is crawling down a hill.


After a comparison between manual vs automatic transmissions for off-road activity, it can be said that each comes with its pros and cons. You’ll agree that one cannot outrightly say the either is the best transmission for off-road activity over the other.

In the end, it comes to your personal preference, the level of control you desire, and what you’re out to get.

Do you want to do it yourself?


Do you want a transmission that will free you from some of the tasks while also being suitable for heavy rock crawling thanks to its slow and precise speed?

It’s left for you to decide and pick a transmission you’ll be proud of and ready to defend against those who settle for another option.