Ford 5R110 Transmission • Problems & Solutions

Ford 5R110 Transmission • Problems & Solutions

Next Gen Drivetrain Research & DevelopmentOctober 02, 2021

Introduction to the 5R110 Transmission:

     Many in the 6.0L and 6.4L Power Stroke community know of Next Gen as the premier choice for 5R110 transmissions and parts such as our famous and proprietary “Bulletproof5R” Valve Body DIY Kit. As a result, many look to us as a wealth of knowledge on the success of this transmission.

     Hearing these calls for information, we conjured this 5R110 Transmission installment in our popular Drivetrain 101 series. Without further ado, we will now analyze the many problems (and solutions) of the 5R110 transmission. To be fair, this unit does have a lukewarm reputation consisting of burnt direct and overdrive clutches, incinerated torque converters and aggressive crossleaks.

     Alternatively, the 5R110 Transmission can be an exceedingly reliable and capable platform. It is with considerable improvement to the valve body, pump, clutch packs, torque converter and more that this transmission can experience a fulfilling life and capacitate added power when applicable. To see our lineup of unique and durable 5R110 Transmissions and parts, click here! 

     In this technical publication, we will observe the inner workings of this gearbox; challenging it’s most popular failures and issues. We will also observe the solutions and modifications necessary to ensure a sustainable and reliable unit. At the end of this article, you will be an expert on Ford’s 5R110 transmission.

A Brief History of the 5R110:

     In 2003, Ford retired the trustworthy and tenured 4R100 transmission in need of something that could endure the the newfound torque (and sustained higher RPM) of the 6.0L motor; manufactured by International. Further, EPA stringencies forced Ford to create a more efficient transmission with an additional gear, to enhance fuel economy. Ford’s solution to this was the questionable 5R110 transmission.

     The 5R110 then continued in use as the sole automatic transmission option for the Super Duty diesels until 2010, when it was retired for the 6R140 transmission for similar reasons. This means it spanned all 6.0L and 6.4L trucks fitted with the 5-Speed automatic transmission.

     As the years have passed and we can now observe the Ford 5R110 transmission with retrospective accuracy, it is now easy to see the prolific flaws the unit presented. Below, we will begin analyzing how the clutch packs of this unit work, when they apply, and for what gears. Using this knowledge, we will assert all of the popular ailments of this unit.

How the Ford 5R110 Transmission Clutch Packs Work:

    The 5R110 is what is known as a “clutch to clutch” style transmission. This means that it does not use hydraulic servos or bands to wrap around the drums to engage any of the gears. Many transmissions (especially older ones without any form of TCM protocol) use bands and servos, but tend to have poorer longevity historically.

     As a result, it is a very attractive feature of the 5R110 transmission to be a solely clutch to clutch unit, one where all gear changes are facilitated by releasing and activating sets of clutches. These units often have excellent longevity compared to “band and servo” style units, but are also considerably more efficient.

     These transmissions often are solenoid controlled and hence have the ability to time shifts considerably better than a unit that relies primarily on hydraulics to calculate shift decisions, such as it’s predecessor, the 4R100. Below is a diagram elaborating all of the shift dynamics of the 5R110, and what components are applied to correspond with those commands.

     As you can see, there are 6 primary clutch packs in this transmission. On no specific order, Overdrive, Coast, Intermediate, Direct, Low/Reverse and Forward. In any given gear, there are multiple clutch packs applied simultaneously. This is because the only way for the 5R110 transmission to deliver power completely through the transmission is by applying at least 2 clutch packs simultaneously. One in the front, and one in the back, though often applying 3.

     Because of this, we can begin to see that the 5R110 transmission offers us a complex method of choosing it’s gears. When contrasted to other 5 and 6 speed clutch to clutch transmissions, this one presents a more complicated pattern of behavior; more akin to Allison or the future 6R140. The susceptibility of this is a heightened probability of electronic failure, making it important for 5R110 owners to understand how to prevent said problems in their own truck.

Problem #1 - The Torque Converter

     This section will be wordy, but there’s a lot of important information to discuss with the 5R110 torque converter. As with most lockup style diesel Ford converters from this era, the lockup assembly comes from the factory with 3 disks. This makes the factory converter technically (we’ll burst the bubble here in a sec) a triple disk unit. Triple disk torque converter from the factory? Nice right?

     As Donald Trump would say, WRONG. Pictured above is a schematic of an upgraded 5R110 torque converter with the factory clutches in place. The 5R110 torque converter IS a triple disk lockup assembly from the factory, however, they’re 3 very small friction elements bonded to one side of one steel and both sides of another.

     Imagine the difference between massive break rotors and pads on a car, versus a car with small ones. The large ones will brake considerably better for obvious scientific reasons.

     The end result is a converter that’s roughly the same durability as alternate converters of it’s time. This was a step ahead of the stock 48RE lockup clutch and featured a stronger stator than the Allison, but it one lacking any tangible winning qualities.

     Additionally, the stall speed is too high. This means the fins inside the stator are too restrictive and the converter is less power efficient (the ability for power to enter one side of a mechanical device and exit the other without loss) than it could be. This is simply some EPA bullshit designed to minimize engine load on electronically fuel mapped trucks, allowing them to idle in gear with less fuel used because less fuel is necessary to maintain the commanded RPM against a higher stall torque converter.

     As we manufacture our 5R110 Torque Converters by hand here in San Diego, CA, we take the time to understand each application personally and build a bespoke torque converter around those desires. This is so that we can identify the stall speed that makes the most sense for the client, you. Our stators are even precision machined here, a very uncommon practice in this industry, enabling us to offer any stall speed you could desire. So that stated, what does someone with a 5R110 transmission need?

Here’s the simple breakdown:

- Low Stall (slightly low, about 15% low, we refuse for our low stall converters to dog the truck down) converters increase torque off the line by improving converter power efficiency. They also run a bit cooler as they produce less friction during the fluid coupling process and enhance towing and acceleration naturally. There is no real downside although it would be less ideal for a large single turbo.

- Stock Stall in the 5R110 transmission is usually nobody’s best option. It is only really best for medium sized single turbo applications who are not large enough to be laggy but are large enough to be potentially hindered by a lower stall converter. Figure this for turbos sized roughly 66 and above with journal bearings, or 69 and above with ball bearings. Usually, even these customers enjoy a low stall converter as they often tow.

- High Stall torque converters are often not a proper fit for roadgoing customers. They’re hot and slow to respond. They also suffer from poor longevity due to the massive speed differences between crankshaft and input shaft during activation of the TCC. However, for customers with massive single turbos, the high slip (and hence high RPM) helps spool these turbos and get the truck into its efficiency range. 

     In short, if you’re the “90%’er”, get a low stall. If you put a bigger turbo on the truck, but still daily drive, you may enjoy a stock stall. If you’re a “big single” type of guy, you will favor the higher stall.

     Lastly, we will speak about the impeller hub. The 5R110 torque converter impeller hub (the component that enters the pump to drive the pump gears) can be known to snap off during heavy towing or racing, but more often towing. A chromoly alternative is standard in all of our torque converters (even the entry level ones!) to ensure that this is not a fear for ANY of our clientele.

Problem #2 - The Input Shaft

     The 5R110 Transmission features the same input shaft as it’s predecessor. It’s a solid style input shaft with no oil circuit in the middle to feed the converter, it instead feeds it through the OD of the input shaft and the ID of the pumps stator support. This is generally reliable in terms of preventing shaft breakage but it simply isn’t perfect.

     If you tow frequently, tow heavy, enlarge your tires significantly without a regear or tune the truck, you enter considerable potential for this style of failure to effect you. There are multiple billet steel alternatives designed to resolve these problems.

Here’s how it breaks down:

- 300M, this is the steel used for most shafts. It is stout, strong and trustworthy. There are more executive options, but this one is safe up to about 800HP and is standard in our Street 5R110 Transmission w/ Torque Converter.

- Maraging, this steel is designed to be an upgraded alternative for applications where 300M is insufficient. We carry this shaft, but don’t use it in any of our builds because we feel if you need more than the 300M shaft, it is simply most logical to purchase the AERMET material shaft.

- AERMET, this is the strongest steel accessible and is very challenging to procure. It’s incredibly rare and exceeds factory tensility and yield by nearly 2:1. It’s incredibly heavy for its small relative size and is safe for even the most aggressive builds. This shaft generally capacitates over 1000HP safely in the 5R110 transmission and is standard in our awestriking Formula One 5R110 Transmission w/ Torque Converter.

Problem #3 - The Direct Clutch Pack

     Ironically, the 5R110 transmission’s biggest issue in terms of clutch packs isn’t necessarily overdrive. Although we will discuss overdrive, as it does fail prolifically, Direct is a considerably less trustworthy clutch assembly. This is for multiple reasons.

     There aren’t enough clutches in the clutch pack. If you disassembled this drum, you’d see it features only 4 small clutches from the factory. Worse yet, the backing plate deflects badly along with the apply plate at the bottom. Both are incredibly thin.

     This coupled with the factory material for the frictions results in a clutch pack that is destined for failure even at stock power. This clutch pack tends to start balding shortly after the 100,000 mile cusp for most users. The alternative is a billet steel backing plate and apply plate combination with different dimensions designed to accommodate additional clutches.

     There beyond, we install additional clutches and steels to facilitate a safe increase in both heat dissipation and torque capacity, followed by an updated thicker snap-ring to replace the failure prone OE unit. Those who tow or have significant added power will also enjoy the crisp and responsive shift dynamics of this specific clutch pack.

Problem #4 - The Overdrive Clutch Pack

     Much like the direct clutch pack, it’s piston, clutch volume and backing plate are simply insufficient so this section will be abridged. What is different is the Torque Multiplication Factor of Overdrive.

     Why is this important? Overdrive is the gear with the highest torque applied to the internal components because it’s the most overdriven. Imagine how the highest gear on a mountain bike feels, versus the lowest. This is how 6th gear and 1st gear feel to the motor. Naturally, 6th gear is going to be the most stressful on internal componentry because of this.

     The solution is, much like the direct clutch pack aforementioned, requires a billet backing plate and additional clutches to experience peak success. Most customers however will see direct clutch issues before they experience overdrive issues. Look for softening shifts into and out of 3rd and 5th gear!

Problem #5 - The Intermediate Clutch Pack

     This is the last of the clutch packs that fail frequently. Frankly, there is little to note here beyond the common trait of low quality pistons and backing plates in this transmission. We also favor adding one steel and one clutch to this pack as additional support for our more audacious customers.

Problem #6 - The Intermediate Shaft

     This part is rather perplexing. It is the second shaft to receive load, but often the first to fail. We see this pattern in 5R110 transmissions but also 6R140’s. What does it mean? This shaft synchronizes in speed with the input shaft on the 3-4 up-shift in a very jarring way.

     This aggressive gearshift can cause the shaft to begin yielding or even crack. Many people feel safe from this failure because they don’t have added power or don’t plan to race anyone, but the majority of our recorded failures of the factory shaft in the factory transmission occurred to customers who were towing.

     The logic behind this is because this is overwhelmingly a mass related failure, as opposed to a power related one. Hence, some people favor this inclusion in their build to ensure absolute security in the most arduous of applications.

Problem #7 - The Rear OD Planetary

     In the back of the 5R110 transmission is a planetary assembly (the type of gearset that creates a set gear ratio) that’s made from soft, low quality steel and tends to come apart at higher power. But, that’s not the only problem.

     When towing heavily or up a grade in a higher gear, this planetary assembly is responsible for being a link in the chain of components that must independently sustain power from the motor without breaking against the mass of the truck.

     Much like most overdrive components, this is prone to failure as well. It is common to see this planetary crack, seize or begin to come apart; often obliterating the core and rendering the customer liable for the core charge. This can be easily avoided by building the transmission BEFORE it breaks.

Problem #8 - The Oil Pump

     Like most factory oil pumps, the 5R110 transmission has a pressure regulator valve system built inside. And further, like most factory oil pumps, it has horrible longevity. In fact, they are often seen imperfect from the factory but survive past the 100,000 mile threshold; they just simply fail to produce peak line pressure numbers like most 5R110 transmissions of any higher mileage do.

     The Pressure Regulator Valve must be machined out in place of a totally different system to properly ensure hydromechanical integrity, a “new OEM pump” is not a solution and anyone who says it is is simply inexperienced.

     Further, the bushing in the factory pump is perfectly straight, and the pump casting often is not. The OEM gets this right by using a thinner bushing that usually doesn’t get too close to the impeller hub. It stays about 0.005” away, and most people will rebuild it with a cheap Babbitt bushing during the rebuild and experience misaligned pump gears, causing a failure like this one.

     To absolve this problem here, use high quality bronze bushings that are later sized to the components they work with, ensuring perfect balance of size, lubrication and quality. We also machine ALL 5R110 transmission oil pumps that we use. If they cannot be machined to perfection, they’re regarded as bad cores and discarded, and it’s that simple.

Problem #9 - The Coast Clutch Drum

     From the OEM, the coast clutch drum is often damaged due to lack of lubrication and excessive wear. Many cheap rebuilds will try to refurbish or replace it with an OEM equivalent. The only logical alternative to keep this drum reliable is welding it to facilitate reinforcement of its failure-prone areas. The clutch pack inside is not a massive failure point, but does benefit from the use of higher quality clutch materials.

Problem #10 - The Valve Body

     This is the biggest failure point in the 5R110 transmission by a considerable margin. The valve body of this unit features 2 main failure points. One is the OEM Manual valve assembly, and the other is the thin paper gaskets used to seal the valve body to the case. That’s right, construction paper, everyone’s most trusted transmission sealing material. (Not)

    The 5R110 Manual Valve Assembly is the piece that moves about the valve body to control gears as you move the column shifter to select one. This piece is grossly problematic in the 5R110 because it's the only valve assuming all of the responsibility, and the remainder of the transmissions operative functions are controlled by the activation and deactivation of solenoids.

     The best upgrade one can use to prevent future problems from this component, or to improve its present operation, is install a different valve altogether. When someone feels a slower than OE engagement into drive or reverse, it indicates leakage at this component and this upgrade becomes vital.

     Now, onto the 2 separator gaskets. Think of your separator plate as the head gasket of your transmission. It’s exposed to tremendous pressure and frequently begins to leak causing catastrophic failure. Our 100% engineered and manufactured in-house “Formula One” CNC Laser-Cut Separator plates are designed both 3x thicker than the cheap factory paper gasket to maximize sealing potential and negate this concern, but also is designed to torque to a near perfect seal on its third torque. 



     These are also single piece plates, rather than multiple paper gaskets that are to be laid together, providing ease and precision during install with the thickest and best sealing separator plate on the market. CNC Lasering also enables us to maintain the most stringent tolerances while also offering a hand finish to both mating surfaces. 

     These updates are a MUST during literally any 5R110 transmission rebuild, and are standard in all of our 5R110 transmissions. In fact, these critical valve body parts are available as their own easy to install kit. If you’re familiar with our bestselling proprietary shift kits known as “Bulletproof DIY Kits”, then you’ve likely seen our 5R110 Bulletproof5R Valve Body DIY Kit.

     This shift kit encompasses all of these critical valve body modifications, and can be installed in the driveway. It is important to emphasize how much the valve body controls the life of the 5R110 transmission, and how it endorses a successful lifespan. Do NOT be the person who thinks a “new OEM valve body” or “new separator gaskets” can fix these complex hydraulic issues.

Conclusion:

     As we can all see, the 5R110 transmission is flawed and imperfect. However, it would be unfair not to recognize that this transmission does have a reputation for surviving some maltreatment before it “bites the dust.” The 5r110 transmission is certainly not a total loss, and with the proper combination of knowledge, components and calibration, can prove to be an exceedingly reliable transmission platform for almost any application. Still have questions? Call in and speak to one of our experts!

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