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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.

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