6 Common Issues With 66RFE Transmission

Transmission problems are not uncommon; many Rams users have complained of transmission problems.

In addition, Rams users have experienced transmission issues with their six-speed and five-speed automatic transmissions.

And these are usually the subject of transmission problems and complaints.

66RFE is a six-speed automatic transmission. The most prominent 66RFE transmission problem for most car owners is that they experience a bump in the transmission whenever they pump the brakes or accelerate. Often the transmission does not accelerate, or they feel a downshift when it does.

What Is A 66RFE Transmission?

A 66RFE transmission is a six-speed automatic transmission. It was first manufactured in 2012 for use on gas engine Ram 2500 and Ram 3500 trucks.

The 66RFE transmission is a hybrid of two other transmissions, the 68RFE and 545FE. However, it leans more in the direction of the 68RFE. Read more about Ram 850RE Vs 8HP75.

The transmission was launched in 1998 as the 45RFE transmission, after which it evolved into the 545RFE.

Then, the manufacturers made a few modifications to the system, and in 2007, it became the 68RFE.

So, the 66RFE evolved from the 68RFE, and it is a lighter-duty version of the 68RFE.

The 66RFE has a single set of splines on the overdrive shaft, a two-stage pump that increases the transmission efficiency by shutting the secondary side at a higher speed, and a single-piece case.

It also uses an overrunning clutch, three driving clutches, three planetary gear sets, and three holding clutches.

Is The 66RFE A Good Transmission?

The 66RFE has many attractive features, and overall it serves the purpose of any transmission. However, it also provides a wide gear range, which is better for towing. 

However, it is not a particularly good or reliable transmission.

Several problems with the transmission even made Chrysler recall several vehicles after the customers complained. 

Common Problems With the 66RFE Transmission

While the 66RFE transmission may be an improvement from the previous transmissions, at least according to the manufacturer, there have been a lot of complaints about the transmission.

Some of the issues have been minor, and the complaints have only involved a few car owners, while others have been quite serious and faced by several people.

The major problem with the car’s transmission is that Ram only put one gear on the truck, and it has a maximum speed of 45 mph.

The manufacturers built the solenoid wrongly, which causes an interference in the electrical connection.

In addition to that, there are several other problems that people have encountered with their 66RFE transmission. They include; 

#1. Noise Coming From Transmission

There have been reports of noise in the 66RFE. Some have complained that it starts as a high-pitched him as soon as the car’s speed increases to 60mph.

Although the noise could stop if the speed goes up, the noise becomes more audible once the transmission shifts into 5th gear.

The issue is present in several vehicles, and the owners have been told that it could be a form of ‘model characteristic,’ and there isn’t much that the dealers can do about it.

Some dealers encouraged the car owners to get more miles on the car, and the problem would resolve by itself. Spoiler alert, it didn’t.

Additionally, different noise in different vehicles does not always sound the same.

#2. Erratic Line Pressure

The line pressure in transmission has to be high enough so that it will be able to stop the clutches from slipping when the vehicle is in gear.

Another issue that 66RFE transmission has encountered is that the line pressure fluctuates from time to time, causing the clutches or bands to shift uncontrollably.

The fluctuation in line pressure also affects gear shift speed.

#3. Burnt Clutches

Usually, riding the clutch is what causes a clutch to burn.

When you step on the gas pedal too frequently and continually engage and disengage the drivetrain, you can generate enough friction to burn the clutches.

However, with the 66RFE transmission, burnt clutches have become a usual problem.

Several users complained that their clutches got burned even though they exercised care.

#4. Hard Gear Shifting

Hard gear shifting is also another problem with the 66RFE transmission.

If your vehicle is having gear shifting trouble, it could have difficulty accelerating, struggle to change gears, and will not have a smooth transition.

Often, drivers describe it as a thud feeling or a cluck whenever the vehicle changes gears.

Some had said it felt like they were rear-ended when the vehicle changed gears.  

#5. Delayed Gear Shifting

Sometimes, the transmission fails to engage or does not stay in gear after it engages.

This failure could be an issue with low transmission fluid temperature or transmission fluid pressure. The issue is quite common with 66RFE transmission.

#6. Transmission Shifting Issues

This issue is also very common with 66RFE transmission. There have been several reports of transmission shifting, which affects the vehicle’s output. 

66RFE Transmission Life Expectancy

Determining how long 66RFE transmission will last depends on a variety of factors. 

  • Your driving habits are one of them. 
  • Whether you use your truck to tow 
  • The weight you usually tow with your truck.

Of course, those will not significantly increase the life of the truck, but different car owners have had different experiences with their trucks.

While some covered over 600,000 miles with their transmissions, others could barely make up half of that.

For some, they said their transmission could only make about 13,500 miles before kicking the proverbial bucket.

For some models, especially 2014 1500, the issues are more severe. So much so that Chrysler had to recall several vehicles.

However, you can try a few things to extend the transmission life because replacing it is quite expensive. 

  • Change the transmission fluid, oil, and filter. Although many manufacturers do not have a specific period for changing transmission fluid, ZF recommended that you change it every 5000 miles.
  • I was hoping you would not use your vehicle to do any heavy towing, I understand that it’s a truck and all, but since the transmission’s not good enough, that can put unnecessary strain on the transmission and increase the wear and tear. 
  • Avoid accelerating harshly; that puts strain on the transmission’s components and reduces its lifespan.

RAM 66RFE Transmission Reliability

Ever since Dodge began the manufacture of trucks, they have been considered reliable and efficient, qualities that have made Dodge trucks one of the most popular brands among truckers.

Currently, there are about 15.5 million trucks in use in the US. 

However, quite recently, the Dodge brand decided to let go of Ram and become a brand on its own. It used to be Dodge Ram, but from 2012, it became just Ram.

Of course, Ram trucks manufactured in 2012 are also good choices. However, they are not as reliable as the brand used to be. 

While a few problems have been reported, transmission reliability issues have been the most common and the most severe.

In addition to that, there have been reports of missing gears and jerky shifts. 

Several people have reported transmission bumps whenever they try to accelerate.

Others have said it feels like the transmission does not have any acceleration and does not downshift properly. 

Who Makes The 66RFE Transmission?

66RFE transmission is an automatic transmission manufactured by Chrysler Corporation.

RFE means Rear Wheel Drive Design And Full Electronic Control System. 

The system is fully electronic, done by the Transmission Control Module TCM.

First, the TCM collects data from the different transmission and engine sensors for the purpose of controlling transmission shifting.

Then, the TCM carries out an operation on the solenoid pack to change the hydraulic flow passing through the solenoid switch valve.

Can You Replace A 66RFE With A 68RFE?

Replacing 66RFE with a 68RFE will not be an easy venture. So it would be best if you didn’t do it.

Of course, there are some similarities between the two, but the two transmissions also have marked differences.

One of the major differences is between the torque converter and the torque converter clutch.

The two transmissions have the same extension housing and output shaft, but the 66RFE transmission has its torque converter in the shell while the 68RFE is inside the shell.

Despite the similarities, 68RFE is a diesel train, and it can handle factory torque of 850, but 66 can only take 385. So, you won’t be able to swap.

The 68RFE is a diesel trans, so swapping it is impossible, especially if your vehicle is a gas truck.

Besides, both transmissions have some issues, so swapping them will compound the issues and may not even function properly.


Most transmissions have trivial issues, while the problems are quite severe for some.

The 66RFE transmission also has transmission problems, the most prominent one being the bump in the transmission that several customers have experienced.

Similar Posts