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August 2022

E4OD Transmission Upgrades for Heavy-Duty Towing and Off-Roading

E4OD Transmission Upgrades for Heavy-Duty Towing and Off-Roading - Gearstar

The E4OD transmission developed by Ford is a heavy-duty unit generally found in the Bronco, E-series vans, Expedition, and F-series trucks. This is a computer-controlled transmission designed for rear-wheel drive automobiles. Ford launched the E4OD in vehicles manufactured from 1989 to 1997, the well-known model years.

Identifying the E4OD Transmission

The popular F-series trucks and E-series vans with the E4OD transmission manufactured from 1989 to 1993 come with a shifter pattern of P-R-N-OD-2-1 and an overdrive cancel switch. But in 1994, Ford launched the 4R70W transmission that also employs a similar shifter pattern. Unfortunately, this similarity in the shifter pattern made examining the shifter to determine the vehicle’s particular transmission highly ineffective.

Ford engines in all 4.2-liter, 4.6-liter, and a handful of 5-liter make use of the newer 4R70W. But diesel-powered vehicles, as well as those equipped with 4.9-liter, 5.4-liter, 5.8-liter, 6.8-liter, and 7.5-liter engines, come with the E4OD. Another way of determining or identifying a truck’s transmission is by measuring the fluid pan. The ideal measurement of the E4OD is 20 inches in overall length, while on the contrary, the 4R70W is 15 inches in length.

Gear Ratios

These are the gear ratios for the E4OD transmission are as follows:

  • 1st — 2.71:1
  • 2nd — 1.54:1
  • 3rd — 1.00:1
  • 4th — 0.71:1

Computer-Controlled E4OD Transmission

The E4OD transmission was Ford’s top-selling electronically-controlled automatic in light trucks. Receives commands from the EEC-IV engine control computer on board. This computer rapidly processes all engine, transmission, and vehicle inputs to determine the best and unique shift points for consistent shift feel and performance. Ford claims several factors determine the shift points of the transmission. These factors include:

  • Engine speed and altitude.
  • The transmission temperature.

Ford was able to salvage 25 percent much better fuel economy in the 1991 F-150 2WD pickup with the E4OD than the 1990 F-150 with the older C-6 transmission.

Recommended Upgrades

Ford’s 7.3-liter power stroke engine was known for its incredible power potential and durability. Nevertheless, the E4OD came on the scene fully equipped on Ford power stroke-equipped available vehicles of the mid-90s. The E4OD worked remarkably well in light-duty applications. However, its design was not tough enough to handle the exceptional needs of most Powerstroke-equipped trucks. Some aftermarket companies offer upgrade components to complete heavy-duty replacement transmission to improve the factory-made transmission significantly.

Aftermarket Modifications 

You can replace several components of the E4OD transmission with upgraded aftermarket parts. These include:

  • Torque converter
  • Transmission control module
  • Pressure regulator
  • Front pump
  • Rear case bushings
  • Sun gear
  • Clutch piston
  • Reverse boost valve
  • Sprags
  • Center support

Adding auxiliary oil coolers can enhance the E4OD to have more excellent reliability.

Essential E4OD Transmission Upgrades and Maintenance

You can enhance the life of your still-functional E4OD by installing a transmission cooler alongside fresh fluid and a filter change. Heat is the arch-enemy of a vehicle transmission, which can easily be compounded by the strain associated with plowing or towing. However, you can perform these simple upgrades without uninstalling the transmission. If you use your vehicle frequently for towing, check out the severe duty maintenance schedule highlighted in your owner’s manual to extend the life of your transmission.

You may also add an external filter so that the latter can work in tandem with the transmission’s internal filter. Upgrading your transmission may require the uninstallation of the gear system. But a pre-1988 E4OD will benefit the most from upgrading by installing the 7-tooth rear lube style rear output shaft. Of course, the truck would have to run a numerically-high rear axle ratio for this upgrade to work efficiently. Installing the output shaft prevents planetary gear failures that come about as a result of poor lubrication. In addition, if input shaft replacements using an aftermarket unit are performed, it will significantly boost shift quality and strength.

E4OD Transmission Reprogramming

The E4OD is an electronically-controlled gear system requiring reprogramming to minimize gear hunting and boost operation. You can bring down gear hunting by adjusting the torque converter lock-up point and line pressure. Aftermarket companies all over the country offer several user-adjustable standalone programming modules designed exclusively for the E4OD transmission. Aftermarket E4ODs also come with unique design elements, such as well-designed transmissions that don’t usually have the general weaknesses plaguing those which are factory-designed. Ensure you only work with a highly reputable aftermarket company when the time comes to rebuild your transmission.

  • Heavy-duty valves.
  • High-quality gears.
  • Superior ball-bearing construction.
  • Magnificent clutch packs.

The price of most aftermarket E4OD units is very close to the amount a rebuild would require. Therefore, do your research to find out how much it will cost you for heavy-duty replacing units before committing to a costly rebuild. You can also enhance cooling capacity by opting for aluminum transmission pans.

E4OD Transmission Overhaul

The primary goal of building an E4OD transmission is to accomplish these:

  • Maximum durability.
  • A minimum build-up of internal heat.
  • Enhance the crispness of overall delivery off and on the road.

E4OD Transmission Rebuild Tips

Keep these tips in mind for your E4OD rebuild:

  • Low reverse clutch. Make use of performance frictions as well as steels to obtain tighter tolerances. Ensure the clearance is between 0,020 to 0.040 inches when installing the low reverse frictions. This is to shorten the delay when going into reverse.
  • Rear planetary. If the three-pinion OE aluminum shows zero signs of wear, keep it. This particular planetary rarely causes any issues. However, you may replace this planetary – if in doubt – with a six-pinion steel version used extensively in the power strokes.
  • Bushings and bearings. Replace all brass bushings showing wear and tear. You should also replace all the bearings.
  • Overdrive planetary. Convert/change the overdrive planetary into steel as the aluminum versions are known to split the neck.

The Bottom Line

Only a professional should handle upgrading your E4OD transmission for heavy-duty towing on and off the road. This is vitally crucial if this is your first rebuild.

4L80 Torque Converter Basics for Reinforcing Speed and Drivability

4l80 Torque Converter Basics for Reinforcing Speed and Drivability - Gearstar

There was a time when drivability, low emissions, and high horsepower were topics of discussion and disputes. Nowadays, auto-shift cars feature speed, fuel economy, and power as vital features every car owner watches out for. These enhancements have also made it easier for car owners to abandon their gearshift. Nevertheless, selecting the correct torque for your automatic vehicle enables you to enjoy the full benefits of today’s technology. This is vital since the 4L80 torque converter links the engine to the transmission while tuning the connection to generate the most power while minimizing heat. Therefore, choosing the wrong torque converter can quickly thwart your dream of a dependable gear-banging since the reliability and power of drivability rely heavily on it. However, if you have plans to enhance your vehicle’s speed while getting excellent fuel mileage regardless of the shift pattern you’ve settled for, you have no choice but to fall right back to torque converter basics.

What Is a 4L80 Torque Converter?

A torque converter transmits an engine’s torque to the transmission. The transmission enables you to move the vehicle along the road. In simple terms, the torque converter connects the power source to the load via the transfer of rotating power from a prime mover to the rotating driven load. They are usually found in automatic transmission cars and efficiently replace the clutch system standard in manual vehicles.

How Does a 4L80 Torque Converter Work?

Transferring power from any powertrain to the transmission is a relatively complicated process. This is because several components move in synch at the same time. Of course, you know that you are just pushing the gas pedal with your foot, flipping a paddle, or moving a gearstick. But a lot goes on right under the floorboards. Each movement beneath the floorboard is carefully engineered and developed to allow for the seamless meshing of multiple components that propel your vehicle into motion.

In Manual Vehicles

A manual vehicle comes with a clutch assembly that gives rise to the connection and disconnection between the transmission and the engine, which drives the wheels. A throttle stop sets the idle of the engines, which signifies the minimum engine speed at which the engine can sit comfortably before it stalls as a result of a shortage of air/fuel mixture entering the cylinders. Without a clutch, the engine would stall when you slow your vehicle down to a stop because the transmission load would drag it far below its workable revolution limit. The clutch brings about the disconnection needed to keep the engine running smoothly and the re-engagement alongside some throttle to get the vehicle functioning again.

In Automatic Vehicles

However, in an automatic vehicle, no proper clutch exists. So instead, the clutch is replaced by a torque converter. The torque converter does the same job as a clutch: it allows the car engine to stay up and to run while the wheels and transmission slow down until they stop. But the torque converter goes about this assignment ingeniously and differently. The torque converter is also referred to as a fluid coupling, which transfers rotational energy via fluid movement from one automated system to another. The fluid coupling can replace the clutch because it can allow the car engine to rotate freely by significantly minimizing the torque delivery from the powertrain to the transmission. The torque converter never connects to the full, as you will feel via the ‘creep’ that occurs when you take off your foot from the brake of your automatic vehicle at a standstill.

A pump that transmits fluid all over the torque converter helps achieve torque control. But this depends significantly on the crankshaft’s rotation. A turbine rotates within the torque converter as the pumped fluid gets in contact with the turbine’s vanes. This gauges the torque that will make it to the transmission via the input shaft. The torque converter’s casing is connected to the flywheel, which also spins at the exact rate of the crankshaft. Within this housing are a stator, the impeller or fluid centrifugal pump, and the turbine. The stator is a barrier to flinging the fluid back to the turbine instead of behind the pump. This action significantly boosts the efficiency of the system. In addition, the impeller flings the transmission fluid into the turbine fins, which, in turn, spin rapidly and transmit torque through to the transmission.

4L80 Torque Converter Basics

Here are a few ways you can speed up your vehicle using torque converter basics:

Maintain Your Car With Premium Fluids and Filters

Using high-quality filters and fluids helps combat excessive heat. However, you must watch out for how much heat your vehicle produces, which could affect how long it services your needs.

Ensure Your Transmission Cooling System Is Adequate

A cooling system helps regulate your engine’s temperature to avoid or prevent overheating. Irrespective of the quality of torque converter you opt for, you need to give more priority to combatting heat. You must consider pairing a cooling system with a high-quality filter and fluid.

Provide the Technician With Thorough Detail About Your Car

Torque converters are not one-size-fits-all. Instead, several manufacturing companies specialize in designing torque converters to fit a particular vehicle’s use and the driver’s specific needs. These companies showcase tech lines that potential clients can use to reach out to them to offer as much information as required about the customized torque converter to be constructed. Information can never be enough at this juncture. But ensure you include essential information such as camshaft specs, engine size, rear-end gear, and tire size.

Make Use of a Lock-Up Converter

A lock-up converter becomes useful for increased fuel mileage, reliability, and driveability. In addition, it can significantly minimize the heating issues of transmissions due to too much slippage from a higher-stall converter. Lock-up converters usually come in an overdrive-style transmission. However, this converter also showcases a clutch that creates a near-direct drive effect when engaged. This helps reduce slippage to the barest minimum, regardless of the stall speed, which successfully helps combat the heat that may potentially destroy the transmission.

Choose Your Camshaft Wisely

Converters and camshafts have a close relationship and could play significant roles in choosing the ideal converter for your vehicle. Camshafts determine the powerband of engine combinations to a very great extent. For instance, a 2,000 – 2,400-stall converter is an excellent choice when considering a cam duration of 248 degrees. On the other hand, a 2,400 or even 3,000-stall converter is much better for a cam duration of about 268 degrees, etc. These values portray that you will need a torque converter with just the right amount of stall for optimum performance while preventing heat generation. An additional advantage is that your engine can sit ideal in gear, especially if you use a stock camshaft. This is why it is crucial to determine the ideal stall speed.

The Bottom Line

The basics of a 4L80 torque converter are highlighted above to ensure you have a unit ideal for your vehicle. In addition, you can determine if the camshaft in your car is the most appropriate one or if a replacement will be needed. Everything boils down to the crucial factors to consider when settling for a torque converter that will always make you enjoy each minute you spend driving on the road.

An Overdrive Transmission Is Awesome, Just Misunderstood

An Overdrive Transmission Is Awesome, Just Misunderstood - Gearstar

When the automatic transmission first appeared on the market in the 1920s, anyone could count the number of gears on just one hand. But today, transmissions are practically all over the place. Honda is currently developing triple-clutch transmissions with 11 gears. According to industry experts, there was a time when transmissions only existed because automotive engines were below par. For instance, V-8 engines can rev up to 6,000 revolutions per minute.

Without a transmission, you will require a car engine that could spin at least three times that high to arrive at top highway speeds. As you may already know, the primary function of a transmission is to take an engine’s RPM and produce the wheel RPM that a particular situation requires. At low gear, the vehicle can pull away from a dead stop, while mid-range gears give rise to acceleration to freeway speeds. High gears ensure the momentum is maintained. This article discusses the misunderstood overdrive transmission and why it was created.

What’s an Overdrive Transmission?

Overdrive refers to a transmission gearing that significantly lowers an engine’s RPM at specific times to bring forth several beneficial effects. In other words, an overdrive turns the driveshaft faster than the engine’s crankshaft as soon as the overdrive is engaged. To get underway, the crankshaft has to turn faster than the driveshaft, which is underdriven. This action gives the engine a significant mechanical advantage over the driveshaft. However, as soon as the vehicle reaches cruising speed, the overdrive ensures the engine turns at a lower RPM than the driveshaft.

This yields better fuel mileage while reducing engine wear. Manual and automatic transmissions may have overdrive, though today’s manuals stipulate that drivers must depress the clutch and then shift into overdrive physically. But from the beginning, this was not always the case. Overdrive‘ is a word that relates to the gear ratio that constitutes ‘extra’ on top of the gearing that generates the peak amount of power. This means the gearing is ‘overdriven.’ Overdrive is practically in every transmission today.

What’s the Primary Function of Overdrive?

The primary function of overdrive has to do with fuel efficiency. A vehicle’s efficiency improves significantly if it moves faster while relaxing its engine. Moreover, since the engine’s workload is considerably reduced, the vehicle’s ride comfort improves and consequently becomes less noisy. The lesser the stress on your car engine, the less stress you will experience. This also boosts your vehicle’s reliability and longevity.

How an Overdrive System Works

When a vehicle is in overdrive, the gearing ensures that the input shaft rotates slower than the output shaft as the car overdrives beyond its peak power point. In a manual transmission, the car is put into top gear – i.e., overdrive – using the stick shifter and the clutch. But in an automatic vehicle, the automobile shifts itself ‘automatically’ into overdrive. 

The Overdrive Transmissions You Need to Know

There is no better time than this period to meet some of the various overdrive transmissions, arranged in no specific order.

General Motors TH200-4R

The TH200-4R transmission first came on the market in mid-sized sedans from General Motors manufactured in 1981. It had a dual-bolt-pattern bell housing, allowing it to fit excellently behind a Monte Carlo SS small-block V-8 and a Grand National’s Buick V-6. The TH200-4R can also be built to efficiently handle big-block power such as Olds, Cadillac, big Buick, big-block Chevy, etc. It was manufactured from 1981 to 1988 and came with an OE rating of 300 horsepower. The dual bolt pattern of the TH200-4R allows it to fit correctly behind most rear-drive GM V-6s or V-8s. No computer is required to operate this transmission, and its overall length is practically the same as that of the TH350. However, you may have to replace most of its internals to handle massive power conveniently.

General Motors 4L80-E

The 4L80-E is a heavy-duty transmission built on TH400 internals and was the standard equipment on 1-ton and ¾ pickups. It was manufactured from 1993 to 2005 and came with an OE rating of 450 horsepower. The 4L80-E can handle massive amounts of power, and its proven strong internals made it popular with the aftermarket. However, some of its weaknesses include its need for computer control. In addition, the transmission’s input shaft can also break easily.

Ford AOD

The Ford AOD transmission, manufactured from 1980 to 1993, was the first production 4-speed overdrive automatic transmission by a renowned domestic manufacturer. This remarkable transmission was constructed more or less around the FMX three-speed. The OE rating of this lightweight and simple transmission is 250 to 300 horsepower. The AOD’s compact design and strong aftermarket support made it incredibly popular. However, this transmission built a reputation for a soft, lazy shift, and its concentric input shaft torque converter lock-up design left a little to be desired.

General Motors TH700-R4/4L60-E

The TH700-R4/4L60-E transmission is the updated version of the 4L60-E and has the internals of a TH350. It was Chevrolet’s backbone 4-speed automatic over the last 20 years and came in light trucks, passenger cars, etc. The TH700-R4 was manufactured from 1982 to 2005 with an OE rating of approximately 350 horsepower. It can be rebuilt with 4L65-E specs and doesn’t require computer control. A significant weakness of the TH700-R4 is the big RPM drop between the first and second gears. Another notable weakness is the sun-reaction shell that tends to break at the input shaft splines.

Ford AOD-E/4R70-W

Ford updated the AOD transmission in the early 1990s by adding electronic shift control and enhancing its strength. The transmission was equipped with a brand-new, wide-ratio gearset and was eventually renamed ‘4R70W.’ The 4R70W transmission is designed to handle lots of abuse and was manufactured from 1992 to 2005. Its 2-inch-wide overdrive band guarantees better holding power, and its stronger input shaft is admirable. In addition, the transmission’s wide-ratio gearset matches shifts excellently to the engine powerband. Nevertheless, the 4R70W is not without a significant weakness: it requires a computer to operate.


The overdrive transmission is understandably one of the most misunderstood components of a vehicle. But it is one of the most vital vehicle parts that enhances the longevity and reliability of any vehicle.

Qualities of a Bulletproof 4R100 Transmission

Qualities of a Bulletproof 4R100 Transmission - Gearstar

The first electronically-controlled transmission from Ford was introduced in 1989 and named the E4OD (E = electronically controlled; 4 = Forward Gears; OD = OverDrive). The E4OD was established on core components of the C6 heavy-duty automatic transmission and was used extensively in several heavy-duty and light vehicles, including the F-150, F-350, F250, and the Bronco. The E4OD came with multiple bolt patterns, which made it incredibly popular for an upgrade or swap. These include big blocks (385 series, not FE), small blocks, modular bolts, and diesel patterns. The 4R100 transmission is rated at 1,000 ft./lbs, which means it is one of the strongest or toughest transmissions ever. Although this is a heavy-duty transmission, the addition of modifications by the owners became one of the weak aspects of the drivetrain.

An Overview of the 4R100 Transmission

The E4OD was updated to the contemporary 4R100 transmission, which is the last rendition of the C6. The 4R100 shares excellent similarities to the E4OD; however, several internal components were adjusted here and there to tackle every durability concern many truck drivers/owners raised. Some issues became visible when this transmission was placed behind the Powerstroke Diesel Engine.

Then, in 1999, 4R100 was enhanced with a PTO (power take-off), which enabled auxiliary equipment to attach readily to heavy-duty vehicles with the transmission. This was when the E4OD was renamed the ‘4R100’ automatic transmission. The 4R100 is a four-speed, heavy-duty automatic transmission that rear-wheel drive trucks with 7.3-liter diesel engine use. It phased out only when the 2003 model – i.e., the 5R110W – dropped. Trucks that carry heavy loads can depend reliably on the 4R100 transmission. The 4R100 and E4OD transmissions share identical gear ratios:

  • 1st gear = 2.71 (excellent for trucks that tow heavy loads)
  • 2nd gear = 1.54
  • 3rd gear = 1:1 ratio
  • 4th = 0.71.

The 4R100 is also a computer-controlled transmission that allows users to use hand-held controllers to modify the characteristics or attributes of the automatic transmission. The 4R100 transmission weighs precisely 270lbs. (dry with converter), and every internal component is enclosed in an aluminum case. It has a fluid capacity of 18 quarts Mercon V (complete with torque converter).

Using a hand-held tuner, the owner/user readily adjusts the line pressure, the firmness of the shifts, and the RPM at which the transmission shifts. Of course, truck owners want all shifts to be as seamless as possible. You can even throw beefier tires on your heavy-duty vehicles and readily adjust your transmission settings to account for the larger diameters of these tires.

The 4R100 – and E4OD – were massive automatic transmissions measuring 27.25 inches long. This is why both automatic transmissions do not apply to non-Ford vans and trucks. In addition, shoehorning the 4R100 into another vehicle will require extensive and expensive modifications. This is why Ford matched the transmission to the following engines:

  • ’99 to ’03 Ford Expedition SUV comes with the 5.4-liter V-8
  • ’99 to ’04 Ford E-Series vans
  • ’99 to ’03 Ford Excursion
  • ’99 to ’03 Ford F-250, larger Super Duty trucks, etc.

Although the 4R100 and E4OD automatic transmissions have identical exteriors, not every component is interchangeable between these unique units. This is why extra care must be exercised or taken to ensure comprehensive compatibility. Moreover, unlike its predecessor, the 4R100 is equipped with a dedicated output shaft speed sensor planted at the rear end of the transmission. In addition, a pulse-width modulated (PWM) torque converter clutch solenoid was also included in the entire 4R100s in every diesel application and eventually in all 4R100 automatic transmissions.

4R100 Automatic Transmission Upgrades

Although the hand-held tuner offers users several basic adjustments your heavy-duty vehicle needs, some truck owners are not opposed to having additional options. The following accessories are some of the few that can help strengthen your 4R100 transmission:

Shift Improver Kits

Shift improver kits are primarily designed to provide users with up to 3 unique options for adjusting their transmission. You can readily adjust or adapt the tranny for towing capabilities, off-road adventures, and heavy-duty conditions.

Lockup Valve Kits

You should opt for lockup valve kits if you want to prolong the life of the torque converter.

Clutch Disks or Kevlar Bands

Consider clutch disks or Kevlar bands if your primary goal is for your transmission to perform optimally under heavy-duty conditions.

Inline Oil Filter

Consider adding an inline oil filter as it ensures the entry of zero debris into the transmission lines or cooler in case you experience sudden and total tranny failure.

Addition of Extra Capacity

You can help keep the transmission cool or at the optimal temperature by adding extra capacity to it with a steel or aluminum deep transmission pan.

Minimize Transmission Temperature

Use an aftermarket transmission cooler with a built-in electric fan to minimize the transmission’s temperature or keep it as low as possible.

Customize Your Ride

You can customize your ride with hardened pump drive tubes, heavy-duty stall converters, and anti-balloon plates.

Transmission Temperature Gauge

This accessory helps you track the overall temperature of the tranny itself. For example, it alerts you when the temperature is climbing near the maximum 200-degree Celsius mark.

Common Issues Plaguing 4R100 Transmissions

Some of the most common problems 4R100 transmissions experience include delayed gear engagement, a hard shift, especially in lower gears, and stalling the vehicle when shifted into the reverse gear. The reverse input drum often wears out untimely, causing your vehicle to stall in reverse since the transmission cannot correctly engage the gear. Therefore, each time you experience these or any other problems with your 4R100 transmission, ensure a qualified mechanic looks it over for quick and inexpensive repairs.

The Bottom Line

The Ford 4R100 is one of the most reliable, heavy-duty 4-speed automatic transmissions on the market and is used extensively in rear-wheel drive trucks with 7.3-liter diesel engines. It was introduced in 1999 as a successor to the famed E4OD transmission. It could conveniently handle higher torque ratings, solved several electronic issues that plagued its predecessor, the E4OD, and was more durable. Indeed, the 4R100 automatic transmission was ‘bulletproof.’ However, this automatic transmission experiences some issues from time to time. These problems were partly why it phased out and was replaced soon after by the 5R110W.