Chrysler 68RFE vs. Aisin Seiki AS69RC vs. Ford 10R140 vs. Allison 10L1000

As modern diesel trucks become ever more powerful, and regulations from governmental agencies become ever more intense, the demand for a reliable, economical, and versatile automatic transmission has become more important than ever. Unfortunately, as transmissions become more complex as they have in recent years, two things begin to happen. One; is that they become much harder to fix when something goes wrong, causing fewer technicians to learn to repair them. Two; is that they become more likely to fail due to there are simply more things that can break. Some of these technological advancements are in our favor, but others are not.

While adaptive shift protocol creates a personalized driving experience, and more gears allow us to improve fuel economy and keep us in the torque band at nearly all times, the addition of countless more moving parts with each new transmission makes transmission experts who pay their bills on 3 and 4 speed transmissions even more likely to swear off these devices

Transmissions aren’t getting simpler, and they’re definitely not getting more affordable. Because of this, it is imperative that we educate the public on these transmissions, how they work, where they benefit, where they experience trouble, and what you can do to make sure they are successful for you and your personal needs.

Compiling thousands of hours of research and development across a diverse landscape of transmissions for various applications, we have a uniquely qualified perspective on these modern transmissions, how they fail, and how they succeed. Our intent is to educate you through objectivity, facts, data, and information to further empower you to understand the transmission you own, or the transmission you may be buying in your vehicle.

This article is an in-depth comparison of all 4 transmissions found in consumer-level heavy-duty trucks today. We share our years of expertise in rebuilding and up-armoring these 4 prolific transmissions. If you’d like to know more about these modern diesel transmissions, their intricacies, and how they compare to one another, then this article is for you.

Introduction to the Chrysler 68RFE:

A run-off of the questionable 45RFE transmission used in the Dodge Dakota of years passed, the 68RFE was implemented for the 2007.5 model year for Ram 2500 and 3500 trucks with the standard output motor. This makes the 68RFE the eldest transmission in this comparison. It has been mostly unchanged for 15 years, with the only notable changes being a few separator plate changes, and valve updates in the pump and valve body. Surprisingly, this transmission is still in use, although it is rumored to be exiting production in the very near future. As one of the most popular transmissions we encounter, we have a great amount of data on this transmission specifically that we will be sharing in this article.

Benefits: The 68RFE transmission does have some notable benefits. Firstly, this is debatably the simplest transmission on this list. For comparison, we can manufacture two 68RFE transmissions in the time we can manufacture one 10-Speed transmission. It’s not radically complicated compared to its peers. This modestly suppresses the cost of repair and replacement.

It’s also important to recognize that 68RFE has a radical amount of aftermarket support. Companies like Next Gen Drivetrain have invented a wealth of upgrades designed to make these products durable and trustworthy. Although the same can be said for other transmissions in this article, but not to the same extent. If you want to modify your 68RFE, there is no shortage of parts to do so.

Drawbacks: As an older transmission, there are many documented imperfections. This may be due to the quantity out on the road. The 68RFE is notorious for struggling to support the needs of the ferocious Cummins motor. In fact, the 68RFE is an evolution of the 545RFE transmission used in the simple Dodge Dakota with many of the parts being directly interchangeable.

The stall speed of this transmission’s torque converter is higher than it should be. Granted, this is likely to minimize engine load at idle to chew down tailpipe emissions, at the expense of low-end grunt and accessible torque. For this, we designed a lower stall stator assembly to be used in this torque converter to adjust stall speed to a much more comfortable figure. This is an important change to enhance the drivability of this transmission.

The 68RFE is known for hydraulic issues that can lead to poor clutch longevity, most often in gears four through six. As the valve bores begin to wear, oil leaks out of oil circuits while they’re being used as well as into others that are not, sometimes creating an array of awkward shifts, loss of power, and high temperatures. Although a valve body or pump would help, it is certainly not the end-all-be-all.

Conclusion: If you don’t modify your truck and service your transmission regularly, the 68RFE can make it as far as 250,000 miles or more if you’re exceptionally lucky. However, for the average consumer, the 68RFE is likely to be a problem at some point in the lifespan of the truck. A 68RFE transmission can be an incredibly durable and smooth-shifting transmission, but certainly not from the factory.

Introduction to the Aisin Seiki AS69RC: 

Intended to be a heavier-duty option than the 68RFE, the AS69RC, a derivative of the older Toyota Land Cruiser transmissions, is largely unmapped terrain for the transmission remanufacturing industry. Beginning life in the 2013 model year, it is the successor to the deeply problematic AS68RC transmission. It was slightly revamped going into the 2019 model year and is still in production today. There are no confirmed plans for the AS69RC transmission to exit production in Dodge vehicles.

Benefits: Although the AS69RC has many notable drawbacks, the transmission does have some benefits. Advantageously, the AS69RC is capable of extraordinary longevity. In fact, the highest mileage we’ve recorded within our company from a factory transmission is 605,000 miles. Granted, this was a customer who runs small tires, factory power, a lightweight trim level, performs religious maintenance, and almost exclusively travels highway miles. Nonetheless, this is an impressive figure.

The AS69RC transmission is capable of towing and hauling very large loads. These transmissions are exclusive to 3500 and above trucks inside the Ram brand and are expected to carry massive weight. It is commonplace to see an AS69RC transmission featured in a vehicle married to a gooseneck, flatbed, or similar. A 68RFE would surely crumble in a 5500, making it necessary to provide this option to Ram customers.

Drawbacks: Though it is true that the AS69RC has some popular advantages, it is not without its failures and drawbacks. Primarily, this transmission is notorious for being difficult to remanufacture, finicky, expensive, and lacking in technical information. This means that when this transmission does fail, and fail it does, it can be exceptionally difficult to find a qualified technician to repair this transmission.

The requirements in terms of tooling and product to rebuild one of these transmissions properly is quite expensive. The result of this is that AS69RC transmissions are naturally more expensive to repair than your run-of-the-mill 4-speed transmission or similar. It is easy to spend $8,000 to $12,000 on even a towing build for the AS69RC transmission. We came to realize that a valve body upgrade is worth its weight in gold on an AS69RC transmission, motivating us to invent countless valves, pistons, springs, and dampeners to resolve these issues.

If both the complication and expense of this transmission aren’t enough to raise concern, the AS69RC shifts terribly. This transmission requires an unusually aggressive fuel de-rate during shifts under load to maintain itself. Although this does contribute to its longevity, this leaves the shift quality poor. Coupled with the valve body’s natural inferiorities, it is an extraordinarily sludgy, unresponsive, and slow-to-shift unit.

Conclusion: The AS69RC transmission features many strengths and many weaknesses. It certainly gets heavy cargo down the road and sometimes lives for long periods of time between internal maintenance. Unfortunately, it struggles at sustaining added power, large tires, or providing a welcoming and dynamic driving experience. Its shift quality is arguably the weakest in this comparison, leaving much to be desired for more enthusiastic drivers.

Introduction to the Ford 10R140:   

After years of general success with the 6R140 transmission, Ford had to find a way to increase fuel economy and decrease tailpipe emissions to feature its most powerful Super Duty (2019+). With this came the advent of the 10R140 transmission, Ford’s first 10-Speed, “heavy-duty” transmission. This unit follows the solenoid strategy system of the prior 6R140, but with 4 more forward gears. It is in production to this day, featuring gas and diesel variants, as well as PTO and non-PTO configurations.

Benefits: The 10R140 was designed with a clear first priority; emissions. Current diesel (and gas) motors are producing more power than ever before, whilst also being expected to achieve greater fuel economy than ever as well. The 10R140 supports higher fuel economy standards and decreased emissions by offering more usable gear ratios to help the vehicle choose the most economical operating range for all conditions adaptively and independently. For this goal, it succeeds.

10-speed transmissions in general offer excellent driving dynamics, when they’re working properly. This is because, with 10 forward gear ratios, they can choose whatever gear ratio they desire. This allows them to always keep you in the torque band when you need it, have maximum pulling power at almost any speed, and all while saving your wallet when it comes time to fuel up.

Drawbacks: As with all things, there are imperfections. Ford is not exactly known for high-quality manufacturing practices or the use of premium materials. As such, the 10R140 suffers from a variety of different problems similar to its smaller brother, the 10R80. From the leaky valve body to the C-D-F drum overheating and pushing its bushing out of place, depriving the drum of oil, the 10R140 has no shortage of documented and prolific mechanical and hydraulic issues.

These are among the most electronically complicated transmissions on the road today. Ten forward gears mean lots of solenoids, wiring, valves, and sensors. These are just more things that can fail. This is why a Toyota with 100,000 miles is barely broken in, and a Bentley with 100,000 miles is virtually unheard of. More parts simply mean more parts that can break. 10R140 transmissions suffer from a confluence of cheap parts, imperfect design, and excessive complication.

All of these factors together leave 10R140 owners likely to require repair in the vehicle’s life, especially when adding power, tires, weight, or any other additional stress. When they fail, which is quite common, they are exceptionally expensive to repair. This means that if you find a technician capable of repairing this complicated transmission, the parts won’t be cheap, and neither will the labor.

Conclusion: As Ford’s first heavy-duty 10-Speed transmission, the 10R140 has some tall expectations. It has succeeded in expanding fuel economy expectations and improving driving dynamics, as many 10-Speed units do. Unfortunately, the 10R140 is cheaply made, expensive to repair, and complicated nature proves to be a fertile area for improvement. Fortunately, we have invented an array of pieces to up-armor these units to ensure that 10R140 owners can be confident in their unique transmissions

Introduction to the Allison 10L1000:   

As a joint venture between Ford and GM, the Ford 10R140 and Allison 10L1000 are sister transmissions. They feature common architecture, design features, and even some interchangeable parts. The Allison 10L1000 transmission first entered use in the 2019 model year to correspond, much like Ford, with a new surge of fuel emissions mandates and ever more ferocious powertrain systems. The 10L1000 is still in use today in heavy-duty GM trucks such as the Silverado and Sierra 2500 and above.

Benefits: As a sister transmission to the Ford, it features many of the same benefits. The 10L1000 transmission succeeds in maximizing fuel economy and minimizing tailpipe emissions; a notable benefit. In fact, the 10L1000 allows these trucks to achieve as much as 23mpg on the freeway. These numbers would be unimaginable mere years ago. If fuel economy is a priority to you, the 10L1000 might prove a viable option.

As with most 10-Speed units, these can drive very well when in good condition. Much like the 10R140, this transmission will always keep you in the torque band under heavy throttle. You don’t have the awkward moments of a turbo not being able to catch up or falling out of the power band. Ten-Speed units are programmed by almost every manufacturer to optimize for access to power under heavy throttle input, making them very nice to drive.

Drawbacks: Much in the way that this transmission’s benefits are largely consistent with its sister 10R140 transmission, so are its drawbacks. Allison has a history of manufacturing durable and trustworthy transmissions. The problem is that this is not a true Allison, but rather an “Allison branded transmission.” But what does this mean? That’s corporate marketing lingo for rebadging someone else’s product with your badge because you think it’ll sell better.

This transmission is overwhelmingly Ford with few Allison influences. The Allison influence is mostly the manual valve, torque converter, and case. Frankly, that’s not very good news. Allison might have a good reputation, but torque converters are their Achilles’ heel. The Ford torque converter may not be perfect, but the Allison is not much better. When designing better converters for these transmissions, we needed to do a lot of redeveloping on both of them. In the Allison, for any decent power, we decided it was best to literally discard the 10L1000 transmission torque converter and start with a 6 Speed torque converter as a base and modify it to function on a 10L1000. It was simply more reliable.

Also, the 10L1000 is more complicated than the 10R140, causing it to suffer from a host of hydromechanical and electrical issues. 10L1000 transmissions are known to flare, bang, and shift at awkward times when they’re beginning to degrade. Although a valve body and pump upgrade can often save you from this, it doesn’t change the fact that the torque converter, drum, E-Clutch hub, and more are known to crumble in this supposedly heavy-duty transmission

Conclusion: As a 10-Speed transmission, the 10L1000 has much to offer in the realm of driving dynamics, fuel economy, and tailpipe emissions. Conversely, this product has trouble being reliable and trustworthy, especially when the truck features added power. Even minor performance upgrades such as a tuning module and some 35s can often cause an Allison 10L1000 to degrade and develop dysfunction. It took a large amount of product development to make these transmissions trustworthy. They’re great when they work, and very expensive when they don’t.

So who’s the best?

As one can see, all 4 of these transmissions are very very different. It would be most accurate for us to assess their unique points of superiority. Because of this, we will be electing the best unit based on individual priorities. They will be assessed based on fuel economy, towing/hauling, and aftermarket potential.

Best for Fuel Economy:
Allison 10L1000 & Ford 10R140 (Tie)

This is a relatively easy conclusion. Ten-Speed transmissions exist specifically for fuel economy and emissions. This is naturally where they are prone to succeed, and seeing mid-20-mpg on the highway is virtually impossible without modifying a truck featuring an AS69RC or a 68RFE transmission. The 4 additional forward gears are bound to produce the best fuel economy figures achievable with these massive and powerful trucks.

Best for Towing & Hauling:
Aisin Seiki AS69RC

This was rather close (AS69RC/68RFE). The 10-Speed duo certainly has a lot to offer when towing due to their strong driving dynamics and easy accessibility of torque in almost any gear. Unfortunately, customers who tow frequently will be troubled by the poor reliability of 10-Speed transmissions. Additionally, the 68RFE is the only unit in this comparison that doesn’t have a PTO capability as it’s an inflated gas transmission, making it non-competitive for this acknowledgment. The AS69RC, despite its imperfections, is most comfortable hauling heavy loads and daring conditions.

Best for Aftermarket Support & Performance: Chrysler 68RFE

All of the transmissions in this comparison can be built and up-armored in some way, but none have the wealth of aftermarket support that the Chrysler 68RFE does. This is a byproduct of it being the eldest transmission featured in this comparison. In 15 years, consumer demand has paid for a massive amount of research and development; not just by Next Gen Drivetrain, but in general across this industry. Despite being perhaps the weakest in this comparison, the 68RFE has the most upgrade support of any of them.

Conclusion to this Comparison: 

The reality, without bias, is that all of these transmissions are excellent in some areas, and lacking in others. None of them are perfect, and none of them are hopeless. No one transmission is objectively and simply, “the best” or “the worst.” Because of this, it’s important that we find objectivity in which units are best at specific consumer priorities. If you’re in the market for a truck and curious about which transmission is right for you, it is best to drive them all. Take home the one that you like most, because that will serve to be the most important factor.

If you already own a truck that has one of these transmissions, know that none of them is a dead end. Regardless of which one you have, should it malfunction, or should you simply expect more out of it, we have gone to great lengths to make a wealth of options available to consumers of a variety of different backgrounds. Any transmission can be up-armored in the right hands. The best thing any of us can do is to simply follow proper maintenance, avoid abusing the transmission, and hope for the best.