What Is A Ford E40D Transmission?

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You just bought a classic truck with an E40D transmission, but you want to know more. What is a Ford E40D transmission?

The E40D transmission was used with Ford’s big block V8 engines from 1989 until 1998. It appeared in various F-series trucks, Expedition, Bronco, and E-series. The drivetrain is known for reliability and was designed to provide the power that Americans were demanding from their trucks and SUVs.

By the time 1989 rolled around, Ford had been using the C6 transmission for over two decades. While the SelectShift Cruise-O-Matic name had been part of the model lineup for years, Ford needed something new. There was an increasing demand for a transmission that could back up the big-block V8s like the 5.8L and 7.5L (which Ford had introduced a couple of years earlier). Americans were exploring their country as never before, using their trucks and SUVs to pull RV campers, boats, or heavier agricultural implements. The public needed a transmission that could outperform the transmissions with hydraulic pumps that did not have enough torque at low speeds. The result was the development of the E40D, the first electronically controlled automatic transmission Ford had ever produced.

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What Is A Ford E40D?

The E40D automatic transmission was used behind the big-block V8s that Ford produced in the nineties. It was available on the ‘89 - 98 F-series (both light and mid-duty applications and the ‘95 - ‘98 7.3L Powerstroke), the ‘90 - ‘96 Bronco, ‘89 - ‘98 E-Series Vans and the ‘97 - ‘98 Expedition. The E40D used many of the same internal components of the C6 but included four forward gears (including overdrive) and electronic shift controls. (Ford had used hydraulics up until this point). The E40D was Ford’s first electronically controlled transmission.

The E40D’s overdrive feature allowed for higher cruising speeds without owners worrying about excessively taxing the engine. Since the new design allowed the motor to operate with less stress, achieve better fuel economy, and watch towing capacities increase, which many people loved.

For the first time, Ford used a dedicated transmission module to regulate solenoids and flow-control systems to regulate the gear ratios. The engineers found that electronic impulses collected data more efficiently, and sent more precise signals. They did a better job of controlling shift points, velocity, and gears for a smoother ride and less shift lag. Owners flocked to purchase the new Ford E40D transmission, excited that Ford had finally built a tranny to handle the heavier load work of diesel applications.

Ford tweaked the transmission In 1995, especially for the 7.3L Diesel, making it even tougher. The engine/transmission produced 425 lbs-ft of torque for the model year, which was more than GM or Dodge were offering at the time. (The factory was convinced that their pickups had the best towing capacity on the market, and Ford wasn’t afraid to tell customers exactly that).

What Are the Specifications for the E40D

The gear ratio for each gear is as follows:

Gear Ratio
1st 2.71:1
2nd 1.54:1
3rd 1.00:1
OverDrive 0.71:1
Reverse 2.18:1

What Happened to the E40D transmission?

In 1999, Ford replaced the E40D with an improved automatic transmission, the 4R100. The new transmission had better performance and a higher torque ability, resolving some of the electronic module issues that had plagued its predecessor. While the E40D shared many components with the C6, the new 4R100 was a different beast. The AR100 had a dedicated sensor on the output shaft, an upgrade that the E40D did not have.

What Were Some Common Problems With The E40D?

While the E40D transmission had a good run in many Ford vehicles, some common problems plagued Ford and frustrated owners. The early E40D transmissions were prone to the most problems, as were trannies with more than 150,000 miles on them.

Torque Converter Failure

One common repair that created issues in the units was torque converters that failed to work correctly. Over the years, owners complained of transmission leaks, clutch pack failure, thinly constructed stators, and even faulty wiring, resulting in lousy connections. (Some technicians reported that when they dropped the transmission pan to drain the fluid, they discovered the factory forgot to put in the filter).

Many of the issues occurred on trucks with higher mileages, which made Ford customers angry. The symptoms varied from shift lag and slippage between gears to overheating, making matters very serious for folks who depended on their trucks.

Center Support Failure

Any transmission with overdrive endures some tremendous forces when OD is engaged and has to maintain high loads at cruising speeds. Many owners experienced a broken output shaft from the overdrive being taxed too much. While Ford bragged about their truck’s transmission and towing limits, the early E40Ds could not maintain overdrive for a long run while pulling a load.

Unfortunately, owners found their trucks with serious transmission problems, losing line pressure, shifting into neutral, or continuously going in and out of overdrive. The failure often set off a host of DTC (diagnostic trouble codes), making the truck light up with warning lights like a Christmas tree during the holidays. Owners were upset that the durability of their truck’s transmissions seemed to be a load of high prices.

Faulty Transmission Control Modules

One of the issues Ford owners experienced on the early E40Ds was they were prone to electrical issues. TCM units were notorious for going out and failing, which shut down sensors and computers controlling shift points and fluid flow modules. Limp mode was a common occurrence for the vehicle. Some owners reported driving down the highway one moment and losing all power the next. A power control module was usually the culprit and had to be replaced. Unfortunately, the new control modules were not cheap, but they were fairly easy to replace.

Rollaway Risk

One of the most frightening issues with the E40D was a broken shift linkage which exhibited itself in the truck being shifted from drive to park (but staying in drive or slipping into reverse gear). Owners complained to Ford Motor Company, but when technicians had trouble diagnosing the issues, they usually recommended replacement. Many of these pickups were out of warranty when the issue occurred, which just succeeded in infuriating customers more.

Is the E40D Easy To Find Parts For Rebuilding?

For the restorers out there, the E40D is probably the transmission that is in your classic if you have a pre-98 truck. Many of these transmissions are still working the fields or on farms, handling their duties like the champs. So, the short answer is that there is a wide availability of parts, but they aren’t cheap.

If you intend to rebuild this transmission yourself, save your time. The E40D is heavy and complicated. There are about a million pieces to it, and as one forum writer put it, “anyone who tries to rebuild an E40D must have a screw loose or be a glutton for punishment.”

Most Ford restorer forums advocated purchasing a completely remaining transmission that could be bolted in and connected rather than completely taken apart and put back together.

They also advised replacing the pumps and torque converter if you attempt the installation.