How to Deal With 4r100 Transmission Problems in Ford Vehicle?

A vehicle is made with numerous software and hardware components. Amongst them, the gear box or transmission plays an essential part in the function of the car, just like the brain and heart in our body. Without a transmission, the engine would not be able to deliver power to the wheels.

In general, there are 2 types of transmission: automatic and manual. The manual device is managed by the user and have a gear selector as well as clutch assembly to adjust levels of gear.

Therefore, you can control the selected gear completely. These days, most car models it made with an automatic system of transmission, which applies a torque converter instead of clutches to change gears automatically without manual effort.

4R100 is a heavy-duty automatic transmission that is introduced in 1998 by Ford. In fact, it is an updated version of the predecessor E4OD. This system is an essential part in several of the most popular Ford cars such as Ford Excursion, Ford Expedition, Ford Super Duty, Ford Lightning and Ford E-series.

When you expose a 4R100 transmission to increased torque load and overload, its operation would be weakened. In this article, we will show you some common problems in 4R100 transmission and also several according solutions that you can do yourself without the need to call a professional mechanic.

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Problems in 4R100 Transmission​

The first thing you need to do is finding out what is wrong with the 4R100 transmission to have suitable solution. The following are some common issues happening in the 4R100:

  • Slipping the transmission off when shifting gears.
  • Fluid leakage from the front part of the transmission.
  • Hard shift in the gears.
  • Car stalls in reverse.
  • Transmission only works in reverse.

Solutions for 4R100 Transmission Issues

If you have any problems with the 4R100 transmission mentioned above, then the following solutions would help to deal with them:

1. Transmission Slipping When Shifting Gear

When the gears are not shifted properly by the transmission, do the belowing steps.


  • Check the alignment of DTR sensor to see whether it slips, it would be a cause for the delay in transmission response in your vehicle.
  • Check the overdrive light to see if it flashes. In this situation, the problem would be from the transmission’s solenoid. This is a serious problem and requires rebuilding, which could save you a lot of money. However, this task requires specialized skills, so you should have it done by a professional mechanic.

2. Fluid Leakage from The Transmission

When you face a fluid leakage in the transmission, it is important to check the following parts:

    • Front seal: If you have not used the car for a long time, then the seal would possibly dry up and get brittle. As a result, the seal would lose its elasticity and ability to keep the liquid, which leads to the leakage.

  • Hub of the torque converter: This component would worn out due to constant use of your car, which requires replacement of the transmission or the torque converter.

In both cases, you need to replace the transmission with an already used one, which would be found with cheaper price.

3. HardShift in The Gears

If you are dealing with a hard shift in the gears, then the accumulator would be broken or stuck in the bone. In this case, you should remove it carefully from the transmission, and see if there is any marks of wear at the bore.

Use a dry and soft cloth to clean it, then check whether the grooves in the accumulator are damaged or not clogged.

Another possible cause would be because of a faulty line modulator valve. You would see it show up at other gears if the problem happens. To fix this, you need to replace with a new one.​

4. Vehicle Stalls While Reversing

This issue would be the result of malfunction in IAC or Idle Air Control sensor, which is often built in modern vehicle models to control the idling RPM of the engine.

This device could last for lifetime of your car, thus the premature failure is probably due to complete or partial jamming in the actuator, which could not control smoothly and lead to frequent stall of the engine.

In most situations, you can resolve this problem by removing and cleaning the IAC sensor. But if this does not work, then you need to replace the actuator or the IAC sensor.​

5. Transmission Only Works in Reverse

When facing this problem, you should examine the forward clutch assembly to see if it is worn out. In addition, remember to check the splines in the forward planetary. Both cases require to replace the transmission.

A re-manufactured or rebuilt transmission has all required upgrades and necessary major alterations, which are made to improve its durability and performance.

​If you buy a 4R100 transmission that is re-manufactured from a famous brand, then you can have a warranty of nearly 3 years instead of a 90 days. The company also provides complete replacement of the transmission when it fails to work normally during this warranty period.


After reading this article, we believe that you have learned all necessary information to deal with common problems in 4R100 transmission.

Once you have mastered in rebuilding the transmission, it becomes much easier to add the features as an improvement, which eventually enhances its performance. In addition, you can also increase the efficiency by installing a transmission cooler to regulate the temperature in the transmission.

To get maximum performance from the 4R100 transmission, you need to manually check its components and operation frequently. Figuring out any problems early could help to solve it timely, which does not seriously affect the performance of the car.​

Related Article: What Should You Do After Adding Too Much Transmission Fluid?


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What Should You Do After Adding Too Much Transmission Fluid?


5 thoughts on “How to Deal With 4r100 Transmission Problems in Ford Vehicle?”

  1. I have a 1999 f250 7.3 super duty. Recently i had the transmission rebuilt (by a vary capable friend) not a service shop. I dont have any worries that is was done incorrectly. The day we re-installed the tranny and test drove it worked just fine. Shifted thru all gears with no issues. My first out of town trip was also uneventful as i drove about 60 highway miles at about 70-75 mph. Overdrive worked etc. On return trip when is shifted down from OD it never did shift back into OD and still wont a week later. I did stop at a transmission shop to have the codes read (OD off light blinked for a short time). however he was unable to read because it said no data sent. He thought maybe a fuse or short could be the problem for that. What are your thoughts?

  2. the ring clip holding the overdrive pack has a problem with coming out of its grove causing that exact problem.there is a updated ring to prevent that problem

  3. I have F250 2001 trans will not shift in reverse and only moves forward and in second gear. How do I fix this problem? Trans rebuilt about three years ago 80k on rebuild no hard pulling.

    • Did you ever find out what was going on with your transmission. I am currently having the same issue with no codes, no engine or overdrive lights on at all. Any help would be greatly appreciated. Thank you


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