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January 2022

Overview of the 4R70w Transmission

4R70w Transmission

The 4R70W, a Ford transmission, is an evolution to the popular AODE and is often used interchangeably. Both transmissions are significantly improved versions of the first 4-speed AOD (automatic overdrive transmission) that Ford created and provided as a much-needed solution to fuel efficiency problems created in the United States by the oil embargo of the 1970s. Chrysler and General Motors followed swiftly with their respective versions.

And since then, several regulations and rules to considerably improve the quality of air and fuel efficiency have been published. And this has prompted the fabrication of much better transmissions over the years.

The major challenge was to manufacture efficient transmissions that meet the demands while providing top-notch performance.

This post will discuss the 4R70W and compare it to other well-known Ford transmissions, its pros, and cons, as well as how to enhance it, especially in terms of getting the best performance.

Brief History of the Ford 4R70W Transmission

Car manufacturers began to wise up in the ‘70s and started manufacturing fuel-efficient vehicles. And for this to happen successfully, the manufacturers had to sacrifice a handful of the speed and performance features that older models exhibited. However, driving fuel-efficient automobiles was environmentally and economically friendly and could cover more miles with far less fuel.

And by the time the price of oil rose about 400 percent, fuel-efficient vehicles had become very crucial. By 1980, Ford created the 4-speed automatic overdrive transmission (AOD).

Although the automatic overdrive transmission was relatively new, it still bore several features of old designs. The AOD efficiently replaced several older transmissions that Ford put out, including the C4, C5, as well as FMX. It wasn’t all that different from the FMX 3-speed automatics since common FMX components – such as the Ravigneaux gear train, etc. – were also part of its components.

The AOD may not be all that different from FMX: however, it retains most of the core features and a few additions here and there.

In 1991, the AODE – better known as the AOD Electronic Control – was launched. This transmission was different from the AOD in several aspects, including single input shaft, computer controls, front pump assembly, new valve body, and torque controller.

Stringent regulations on fuel efficiency improvement as well as air quality and significant improvements in technology have called for much better transmissions while making room for superb performance.

The truth is there is no perfect stock transmission. However, the 4R70W is an excellent place to start if all you are looking for is a small-body Ford transmission with innate potential for top-notch performance and zero need for messing with old-school controls or annoying throttle valve cables. But then, the 4R70W is also not a great place to end your search either.

The 4R70W Transmission Specs

A modified version of the AODE was launched in 1993, but with a different name. Nevertheless, both transmissions are interchangeable. The 4R70W arrived at the scene with the following specs:

  • 4 forward speeds
  • Rear-wheel drive
  • Wide gear ratio
  • 700 pound-feet torque rating

The gear ratios of the 4R70W transmission are:

  • First gear: 2.84
  • Second gear: 1.55
  • Third gear: 1:1
  • Fourth gear: 0.70

The respective gear ratios of the AOD are:

  • 1st gear: 2.40
  • 2nd gear: 1.47
  • 3rd gear: 1:2
  • 4th gear: 0.67

You can see the difference in gear ratios when you compare them side by side. It should also be noted that the cases and valve bodies of the AOD, AODE, as well as the 4R70W, are different. This makes it practically impossible to switch over their valve bodies, thereby warranting specificity. 

But you can actually take the gear train of the automatic overdrive transmission and shove it right into an automatic overdrive transmission electronic control.

Which is Better: the AOD or 4R70W?

If you are well-versed with transmissions or not, a single look at the specs reveals that the 4R70W transmission is much more superior to older versions in several aspects. But this is not to imply that it will remain the best option at all times.

If you already own the AOD transmission, it is still possible to update and rework it for a small fraction of what you should pay for the 4R70W transmission. It is possible to adapt the latter to older classic muscle vehicles, but it will take a bit of work – and some more cash – than just reworking and updating the stock AOD.

The same thing applies to automobiles with the AOD Electronic Controls in the 1990s. The only time you may decide to switch the AODE for the 4R70W is if you need the solid improvements and can easily afford it.

Pros and Cons of the 4R70W Transmission

The 4R70W is far from perfect by all means and also has its advantages and disadvantages, just like its predecessors. Here are some of the excellent qualities of this remarkable transmission, as well as a few shortcomings you should be aware of:

  • Pros

The most significant benefit that the 4R70W transmission brings to the table is its considerably improved overdrive band, a pretty solid input shaft, better front pump, and improved pinpoint precision control.

Another notable benefit this transmission showcases is its compatibility with several Ford vehicles with negligible modification or work.

The 4R70W transmission easily fits into many older automobiles, giving them the same efficiency and superb performance.

  • Cons

Overloading the 4R70W transmission is a bad idea. And that is why you should know what it can – and what it can’t – do. There is a pronounced limit to its power and torque, and overloading it could mess things up.

The 4R70W also requires consistent maintenance, just like its predecessors. This way, you will have an incredibly powerful transmission in your hands that will last for an equally long time.


As mentioned earlier, no stock transmission is perfect in every aspect. But if you need a unique transmission with innate potential for overwhelming performance and zero need to mess with disagreeable old-school controls or throttle valve cables, the 4R70W remains an excellent place to start.

Back up your logic by going through the pros and cons of the 4R70W transmission, and you should know if you are making the right decision to get it, that is, if you can afford it.

Start Your Own Ford AOD Transmission Rebuild

ford aod transmission rebuild - Gearstar

The oil crisis in 1973 brought a very harsh reality for motorists in America: fuel was going to become more expensive. And the only way out is to manufacture cars that use less without really sacrificing power more than necessary. And even when the oil crisis repeated itself much later within the decade, the Ford AOD (automatic overdrive) transmission came into the picture.

What to Do Before Your Ford AOD Transmission Rebuild

Before you start up a Ford AOD building project, you need to get your hands on the tools that will enable you to do the job. And a proper work setting is vital in order to make the project a success as well.

This is because automatic transmissions are known to cover a wide variety of incredibly tiny precision parts such as balls, valves, clips, pins, springs as well as other items. You need to also ensure that your workshop is impeccably clean, orderly, neat, and of course, well lit.

This last aspect is vitally important because some parts are tiny, and you can easily overlook them. This is why your shop environment should not have low lighting or lots of clutter. Every component is vital, especially when it comes to automatic transmissions. If you discover any parts left on your workbench when you are done with everything, then your fate is sealed: you are in deep trouble.

Once again, cleanliness is crucial and should never be taken for granted when working with automatic transmission. This is because the smallest grit or dirt can throw you off as it disturbs automatic transmissions’ precision tolerances. And when this happens, it can lead to severe malfunction and extremely poor performance.

Tiny grains of sand or house dust can cause a seal to tear or a valve to stick unceremoniously. All these could have severe impacts on the transmission function. And this is the primary reason why automatic transmissions should be bagged at all times, especially when you are not working on them.

If you live in an area known to be dusty, you should consider bagging your transmission and stowing it away in a clean storage room.

Safety Precautions to Stick to When Working On an Automatic Transmission

Ford AOD transmission rebuild also come with several safety issues that you will do well to keep in mind. Bear in mind that components and vehicles in general can maim or kill you if you are not so careful.

But you can avoid getting killed or maimed if you follow these suggestions carefully:

  • Use Only Nitrile Gloves

These are somewhat similar to the latex gloves commonly used in clinics or hospitals. Use nitrile gloves to protect your hands from solvents or other harsh chemicals. Undue exposure to these substances can cause severe skin dryness and even cancer.

Nitrile gloves also protect your skin from sharp edges of aluminum and iron castings.

  • Use Muffs or Earplugs

Power equipment can emit high-frequency noises which are severely damaging to the human ear. Therefore, use muffs or earplugs to protect your ears from the din of the equipment, electric motors, compressors, or gear and belt drives.

  • Protect Your Eyes and Face

Use goggles, safety glasses, along with a full face shield in order to protect your eyes and your entire face from flying debris, metal, and other foreign matter.

Keep rotating equipment away from you.

How you hold a cutting wheel and grinder is also vital and determines how safe you are. Therefore, make sure you keep the rotation of your cutting wheel/grinder away from you.

  • Get A Good Respirator

You should also protect your lungs with a suitable respirator since you may be working with alcohol- or petroleum-based cleaning solvents. Use respirators with charcoal cartridges to keep all particulates and chemicals away from your lungs.

Organizing the Components

Now that everything is set, you should start working on your AOD/AODE/4R70W build. Steels and clutch friction discs must mate with utmost precision. Ensure sliding valves glide right through the valve body without any hassle. Clean seals and servo pistons, and ensure they bind well since dirt can cause tolerance issues.

Tools, Equipment and Supplies

Ensure you have enough tools, equipment, and supplies for your work on the Ford AOD transmission rebuild. Most professional transmission workshops have ideal transmission-holding fixtures designed to support all transmission cases during assembly and disassembly.

You need compressed air for clearing debris. Check clutch pistons for perfect function. This is why it is highly advisable to carry out this entire process at a professionally-equipped workshop.

A Step-By-Step Method to Follow for Transmission Removal

Step 1: Get rid of any item in the way

Automatic transmission removal starts with removing any item that may get in the way. So, begin by removing exhaust systems, parking brake cables, wiring, H-pipe assemblies, etc. The latter may be difficult – but not impossible – to remove if it is welded together.

Step 2: Get rid of crossmember

As soon as the automatic transmission has been supported, unbolt and remove the crossmember. Replace crossmember bushings and then mount it with anything that ensures you win mileage and time.

Step 3: Dispatch the driveshaft

Create reference marks at the yoke and flange. This enables you to reinstall them easily in the same position by aligning the reference marks. This is where you rebuild the driveshaft and balance it with a slip yoke and new universal joints.

Ensure a professional check out the driveshaft for run-out or any other stress issues.

Step 4: Disconnect all accessories

Unplug the TV cable and shift linkages. Take a quick note of both the TV cable adjustment as well as the installation and cable manual-shift linkage before disassembly.

Step 5: Remove the Exhaust heat shield

The next step is to remove the exhaust heat shield. This makes it far easier to remove the automatic transmission. The job of the heat shield is to prevent the onslaught of extreme catalytic convert heat. When it is time to reinstall, you can reuse the heat shield.

Step 6: Remove the starter and Unplug the battery

Unplug the negative cable of the battery and then remove the starter. The small trigger lead always fires the solenoid in this application.

Step 7: Remove dust shield and bellhousing

Remove the flexplate/torque converter dust shield. This reveals the entire converter-to-flexplate locknuts and studs. You will set eyes on 4 locknuts. Replace them with new ones.

Rotate the engine manually, and you will be able to access the 4 locknuts.

Step 8: Disconnect the torque converter and flexplate

Remove the locknuts that keep the flexplate in place in order to free up the torque converter and automatic transmission. Make sure you use an excellent thread locker as well as new locknuts.

Step 9: Disconnect all transmission cooler lines

Disconnect every transmission cooler line. You need to replace both the cooler and the lines even if your automatic transmission did not fail. Band friction material, metal, and other debris can quickly become trapped in the cooler and lines. This could severely damage the new transmission.

Step 10: Unfasten bellhousing and lower transmission

Removing the bellhousing bolts may require the use of a 5/8-inch socket. You can remove most of these bolts right from underneath. Removing the top 2 bolts requires box-end wrenches, though this depends significantly on the firewall clearances.

Step 11: Examine the flexplate

Examine the flexplate for ring gear damage, cracks, and proper installation. You should also inspect the starter drive and search for the pan gasket leakage on the engine as well as the rear main seal.

If there are any problems or issues, correct them before you start the reassembly process.

Step 12: Get set to teardown

After removing the automatic overdrive, it becomes ready for a teardown. Teardown gives you the opportunity to learn more about transmission failure, i.e. if any has occurred. It also gives you the chance to scrutinize wear patterns that could cause severe problems in the future.

Step 13: Remove and inspect electrical components

Remove all sensors, fittings, and switches. Strip the transmission case completely bare for cleaning.

If you are carrying out the ford aod transmission rebuild at home or any other place other than your workshop, make sure all the parts have been cleaned professionally. Pressure-wash them with a suitable solvent if you are on a tight budget.


This is the step-by-step method of rebuilding and modifying a Ford automatic overdrive transmission. Make sure you adhere strictly to the steps and precautionary measures before you embark on the project.

Overview of the Performance 700R4 Transmission

Performance 700R4 Transmission - Gearstar

Having a piece of basic knowledge on how to service your 700R4 transmission is not a bad idea, so coming down here to read the step-by-step approach on how to get it done will be a worthwhile journey.

But before then, you must note that the 700R4 automatic transmission, also known as the “hydramatic,” was designed and launched by General Motor’s company in 1982 as a perfect substitute for TH350.

The 700R4 automatic transmission is a four-speed trans with powerful 30% overdrive situated at the fourth gear. This magnificent design was built to improve and economize fuel, among many other things.

That being said, doing an absolute auto transmission rebuild is an interesting option left only to the professionals, but adding one or two shifts or doing the overall trans service is something that anyone can tackle with the help of this guide.

How to Service Your GM 700R4 Transmission

The first thing to tackle in your sojourn to service your 700R4 transmission is the fluid. While it plays a key role in the auto trans, you can begin by replacing the filter. After all, that’s what the servicing is all about. So changing your 700R4 transmission filter regularly can extend the auto life cycle.

Without mincing words, below are the step-by-step approach on how to service your 700R4 transmission. This procedure is practically feasible for all seasoned General Motor (GM) automatic transmissions.

Step 1: Remove the Rearmost Bolts

The first thing you need to do in other to home-service your automatic transmission is to remove all the rearmost bolts. But before losing them, you should have a big drain pan waiting and ready.

That way, when the bolts are loosened toward the front rail, you will be able to control the pool of fluid that will flow out of the trans pan, and as such, you won’t make a big mess of yourself.

Step 2: Remove, Scrape and Clean the Gasket

After loosening the rearmost bolts with a stream of fluid flooding out of the trans pan, gently and completely place the pan on a clean earth surface so that the gasket can come off it with ease.

Sometimes, the gasket may come off in pieces, and at times, you may have to remove them manually. After which, you will scrape and clean the mounting surface. Take notice, it requires a thorough cleaning.

If it pleases you, you can use the solvents and carb washer to get the gasket pan cleaned up. And you can equally use a water-based degreaser (if you have it) in your garage sink.

Step 3: Remove the Transmission Filter

Having removed and cleaned the gasket, what is next in your 700R4 transmission services is to remove its filter. While attempting to remove it, what you see next is called valve body.

If you’ll be modifying and installing a shift kit, the valve body is what you are going to remove, but our main focus here is the filter and not the other way round!

So while you don’t have anything to do with the valve body, try to focus on how to safely remove the filter as this is exactly where many people do encounter problems when doing the transmission service themselves.

The problem there is that the seal that plugs the filter into its case often gets stiffed, harden, and stuck-up there. And if you attempt to shove another filter on top of it, it won’t seat, and it won’t fit into the pan.

So if you encountered a similar problem along the line, a plier with a pick and needle-nose will solve the problem.

Step 4: Trash the Drained Gasket Pan and Filter

If you are reading step 4, it means you’ve successfully removed the filter, and your gasket pan is fully drained. If yes, then keep reading but if the reverse is the case, repeat step 3 and check if your gasket pan is drained or still flowing.

At this point, the drained filter and gasket pan should be dropped into the dustbin, the fluid should be recycled, and the rearmost bolts should go into the sink.

Thereafter, everything should be cleaned up, and get ready to reinstall the transmission back, including the new filter and gasket.

Step 5: Install the New Filter

Remember that the old filter and gasket pan had to be trashed, so there is a need for new ones to be reinstated. Before you install the new filter, add a little fluid to its seal so that it can easily seats well in the case.

Having applied the fluid, gently push it into its place and after that, get the gasket pan ready. In doing that, wipe down the gasket pan mounting area with a lacquer thinner to ensure that it is free of debris.

Step 6: Install the New Gasket Pan

When you are sure that the gasket mounting area is free of any debris, apply a little adhesive to the pan, set it in place, and start tightening the bolts again.

In case you encounter any problem in so doing, try snugging the bolts down using another alternating pattern. But before then, make sure that the pan bolt you are using on the torque specs is not more or less than 80-inch-pounds.

Step 7: Top up the 700R4 Trans with Fluid

If you are reading this, it means you are almost done servicing your 700R4 automatic transmission for good. All that is left is for you is to add some fluid to replenish the lost ones in the cause of servicing it. Usually, auto 700R4 will take nothing less than six quarts of fluid after a service.

Step 7: Testing

Having added some fluid to your 700R4 transmission, your job is completed. However, you may have to run the vehicle to temperature, check your dipstick and carefully study its overall response to see if it is balanced or not.

But if you carefully follow the above steps, your vehicle will produce some sounds that are appealing to the ear.


There is no big deal on how to service auto 700R4 transmission, all that matters is to open the trans and change its filter and gasket pan. If you can keep repeating this process occasionally, your engine lifespan will increase.

How to Modify Your Ford AOD Transmission to Perfection

How to Modify Your Ford AOD Transmission to Perfection

Ford’s Automatic Overdrive (AOD) was firstly used in 1980 before it became an overly electronic controlled transmission AOD-E in 1991. There are simple, yet effective ways to modify your ford AOD transmission to perfection and that is what this blog post is covering.

Prior to commencing your Ford AOD transmission modifying project, it’s necessary you have an ideal work setting and most importantly, the required tools for the job all available. 

Since automatic overdrive transmissions entail several tiny precision parts like clips, valves, balls, springs, pins, and the likes, your workshop environment should be in order, neat, and well lit.

It is possible to modify your Ford AOD transmission perfectly by replacing some of its core internal components using aftermarket kits. Envision the Ford vintage AOD as a core component that needs to be replaced with the perfect parts to boost its performance.

Like Trudi Dufek’s 1963 Ford Falcon Sprint modification, modifying your vintage car means taking it to another level, and such is like the ace of spade to win a lady’s heart. Of course, we are going to show you how to make your AOD better.

Now, do consider the following points on how to modify your Ford AOD transmission to perfection:

1. Use the Perfect Aftermarket Parts

Selecting and using the right aftermarket parts will determine the kind of performance you get after modifying your Ford AOD transmission. The wider AOD overdrive band and reverse drum will take the load better.

When done right, the transmission should be able to take 800-1200 horsepower (hp) in some cases which overset or translate into a rugged and dependable AOD. You can also take it a step further should you go for the 4R70W. It has the ability to increase car acceleration as a result of its better gearing. 

In the same vein, the 4340 chrome-moly durable input shaft should be used too since it can deal with the input shaft breakage puzzle glaring in stock shafts. Consider the “A” Overdrive servo too to achieve the clamping pressure of the greater Overdrive band.

2. Adjust the Throttle Valve Cable

Modifying your Ford AOD into perfection also requires you to adjust the throttle valve cable. Hence, it’s very crucial you note that the throttle valve (TV) cable can be adjusted in two different ways.

One involves using the pressure gauge, and the other is doing away with it. However, you should make use of the pressure gauge by screwing it into the pressure port line which is located at the right side of the AOD transmission case.

Similarly, with a pressure gauge already screwed into the pressure port, you should see 0-5 per square inch (psi) at idle speed and 30 pounds’ psi per normal acceleration. 

At wide-open throttle, you should at least see 85 pounds’ psi of the line pressure. Thus, if the speed is idle, there will be a slack tension on the TV cable, meaning there should be no tension and no slack either.

Equally, if you will go for the other available option i.e. adjusting the TV cable without the pressure gauge during the installation process, the cable tension should not be slack also.

Be that as it may, applying the gear shifter should bring a gentle engagement result in place of a jolt. At this point, a test drive is very necessary starting with a soft acceleration and then after, a hard acceleration.

A light acceleration should produce a firm upshift time with a speed increase while a hard acceleration should deliver a delay but quite firm shifts. In case there is slippage, the cable tension should be increased. 

That is to say, under no circumstances should there be slippage. If there is any, the cable tension should be increased, or else, the transmission will overheat and burn.

3. Torque Converter Proper Installation

When it comes to Ford AOD modification, special care is needed for the torque converter installation because nothing stings AOD installers more than inappropriate torque converter installation.

Therefore, make sure that the torque converter is properly installed on both the basic and secondary shafts, front pump rotor and stator support to prevent front pump failure or damage. 

Also, make sure that there exist three moments that will enhance the converter to conveniently pop to the next rank. You will know if the converter has been placed into its right position the moment your hand can’t pass through the bell-housing and the converter.

4. Use AOD Adaptor and Conversion Kits

In the process of modifying Ford AOD transmission to perfection, torque converter installation and adjustment looks straightforward, when an orderly and methodical approach was used to ensure success.

However, with an AOD adaptor and conversion kit, you will be able to freely install an AOD in almost any vintage Mustang too, excluding the 200ci and 170ci inline-sixes.

Specifically, the California mustang AOD conversion kit doesn’t have an AOD adaptor. However, it does have a trans mount, flexplate, cross-member, throttle valve cable, ‘65’- ‘66’ parking brake bracket, slip yoke, adjustable manual shift linkage plus installation hardware.

Lastly, these kits will aid you to get overdrive mounted in your car efficiently in no time making your work lots easier with more productive results.


If you can commit your heart to it, you can build a perfect AOD transmission today. It all starts with making a choice between the 4R70W or AOD-E as your AOD core. You will also have to carefully pick the perfect internal components. After all, they will contribute immensely to the performance level of your Ford Falcon machine.

To round things up, the above-explained are simple but effective ways you need to master how to modify your Ford AOD transmission to perfection via the use of aftermarket kits and off-the-shelf components.