68RFE Stuck in 4th Gear – Reasons and Ways to Fix

The RFE series is a group of automatic transmissions made by Chrysler. The 68RFE is one of the most common transmissions in this series. Commonly used in Ram 2500 and 3500, its efficiency makes it very reliable. 

68RFE transmission highlights

• Average lifespan:190,000-210,000 miles
• Reliability Score:High
• Prone to minor issues:Sometimes
• Price for repair after failure:$1,300-$1,800
• Price for replacement:$5,500-$6,500
• Availability of parts:Average
• Common problems: Valve body may get clogged, leaks are possible, pump isn't eternal, electronic control problems.

An Overview of the 68 RFE Transmission

RFE as mentioned earlier is automatic transmission belonging to Chrysler. However, RFE is an acronym, meaning Rear wheel drive design and Full electronic control. In the RFE series, there are three groups of automatic transmissions.: 45RFE/545RFE, 68RFE, and 65RFE/66RFE. 

Arranged in order of production, the 68RFE was released as an upgrade to the 45RFE/545RFE. 68RFE production started in 2007 as the transmission for 2500 and 3500 pickup trucks. These trucks having the 6.7L Cummins diesel engine were the first to be equipped with this transmission.

The 68RFE has a simple design and its performance is like that of its predecessor. These similarities do not mean equality as this model packs some extra improvements.

Improvements found in 68RFE transmission include:

• bigger bell housing with various bolt drafts and patterns to allow diesel motor
• altered inner parts to deal with the expanded torque power of diesel motor
• changed gear proportions and transmission Regulator programming for bigger application
• downshifting requires no second gear like the 45RFE and 545RFE transmissions

The Transmission Control Module provides comprehensive electronic control (TCM). Depending on the year and use, it might be a standalone module or work in conjunction with the Powertrain Control Module (PCM). To manage transmission movement, the TCM uses data from several transmission and motor sensors. 

The TCM operates the solenoid pack to direct water-driven movement through the valve body to separate transmission grasps. The solenoid pack is simply attached to the valve body, and its connector extends from an orifice on the transmission's left side. The 68RFE uses the fourth gear for limp-in rather than the second and third.

Possible cause of this Transmission failure

There are a few notable causes of transmission failure. If your vehicle's gear is stuck in the 4th without any prior transmission issue, you should consider this list. You might go through this list and still not get a fix, what your engine needs might be a visit to the trans shop. Before trying any of these methods, troubleshoot the issue first and record the machine error codes.

Some causes of this transmission failure include:

• Low Transmission Fluid

One of the causes of this transmission getting stuck in the 4th gear is when there is low Trans fluid. A lot of users do not check their fluid regularly or clean the filters and this can cause transmission failures. 

Having a low transmission fluid doesn't necessarily mean you do not change it. A leaky transmission can lead to loss of transmission fluid thereby resulting in a transmission failure. Another cause of low transmission fluid is excessive heat in the transmission module, which eventually dries the fluid.

Low transmission fluid can cause damage to the other parts of the engine if not handled quickly. Hence, you should ensure that once this is tested, get it handled before driving. 

• Loose Valve spring

Another issue that can cause a transmission issue with the 68RFE is a loose valve spring. The valve body is one of the components of the transmission and a loose spring will badly affect transmission. Although it is an uncommon cause of gear failure, it should not be ruled out.

• Cold weather

Although some vehicle owners argue that they experience this issue even in warm weather, cold weather should still be considered. In a cold environment, operating your vehicle without raising the temperature to at least 1200 F can be dangerous for transmission. 

• Loose wiring

When there's a loose wire in the transmission module, it can trigger the limp mode and get the gear stuck. Troubleshooting tests can ignore this error or even get an engine light warning. This situation should be checked quickly to avoid further damage to the solenoid valve.

• Low battery voltage

There's a required amount of charge that should reach the transmission solenoid and any value not within this range can cause transmission failure. A value less than 5V can indicate failure in the wiring of the pressure sensor.

• Triggered Limp-In Mode

There are two distinct limp-in modes for the RFE transmission. The first type controls the opening of the trans relay (separating the typical 12V feed to the solenoid module) and is known as "orderly shutdown" (or OSD). Anytime you are in Drive, the trans will run in fourth gear (with the converter opened) as a result. When the vehicle leaves a stop, it will feel very sluggish. Most errors are handled in this manner (causing the limp-in).

"Logical limp-in" is the name given to the second type of limp-in. In this mode, the solenoid module is still fed by the trans hand-off, but the TCM controls the transmission of only the first and fourth gear wheels (while in Drive), once more with the TCC always open. Therefore, if your transmission normally shifts into first gear but then immediately shifts into fourth speed (and stays there until you grind to a halt), you are in a real limp-in. The conventional response to a gear ratio issue is rational limp-in.

Numerous "normal" defects (which result in OSD) are electrical faults brought on by damaged wires, defective solenoids, defective sensors, etc. However, if you're suffering logical limp-in (1st and 4th gears), your transmission likely has a burned clutch, which in the case of the 68RFE is usually the OD clutch (weak link).

Fixes for this Transmission issue

• Restart the engine

If you have an emergency that must be attended to and your vehicle gets stuck on the 4th, it may be horrible. For a temporary fix, restarting the vehicle will be fine. While this is not an advisable option, it can get you out of tight spots when you need it.

• Change the Transmission fluid

Most trucks have a recommended use of ATF+4 transmission fluid. Ensure to have at least 11 quarts ready even though you might not need as much. Ensure that you change your trans fluid every 50,000 miles to prevent any further issues.

• Order a new 68RFE

Ordering a new transmission panel can also be the way to go. If you're not sure about what part of the system is malfunctioning, you can order a new one. In some cases, you might get a P0700 error shown as 'General Trans Error', this is one of the many codes representing an issue with the transmission system. 

If your transmission unit is also beyond repair, ordering a new one is the only choice. Note that when you order a new 68RFE, you are getting a refurbished version. Several engine companies have produced modifications with enhanced capacities and finding a new and unmodified one will be very difficult.

• Replacing the shift solenoid block

The most well-known cause will be the solenoid pack that is situated inside the transmission lodging under your vehicle. Before you start You will require force torques both foot-pound and foot-inch, and some ATF-4 liquid. 

You'll need to eliminate the transmission skillet and it will make a significant wreck, so be prepared with a dish or a tub. Delicately unscrew the fasteners and tap on the container let it dribble however much you can.

The next thing is to detach the solenoid association coming from the highest point of the dish region on the driver side of the trans block. 

There's a red tab you pull down in the center of the connector, after that you pull down the white plastic bar. You'll need to unbolt the solenoid block. Remove the solenoid block from the transmission and start depleting it. To clean the transmission pan, ensure that you use a soft or plastic brush since the panel is fragile. 

The next thing is to loosen the Torx screws and there are about 15 of these. However, while loosening these screws, be careful not to remove those placed at a right angle. All the others should be carefully loosened. A T20 should work for loosening these bolts

Once you have loosened the whole block, replace it with the new one. Remember this order to replace the block. The O-ring goes in first and requires a 105-inch pounds torque to be properly fitted. Ensure that the filter O-ring is properly keyed into its block, you can fix it into position gently using a hammer. 

Afterward, put back the solenoid block, the screw filter, and lastly, the flat filter. 

• Transmission filter 

Replacing the transmission filter is also a way to handle the gear getting stuck in the 4th. When the filter gets dirty, it causes the transmission to malfunction and this could result in the issue. Check the instruction on changing the solenoid valve on how to replace your transmission filter.

Final words

Having the transmission of your truck stuck in the fourth gear can be very devastating. The cause of this may range from replacing something between a few dollars to hundreds of dollars. However, the first step to take in this case remains to get a machine test to get the error codes.

In case you choose DIY and decide to change the solenoid pack, do it with care and be ready with your tools. Also, don't poke into the transmission module without prior knowledge of the component.