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In Transmission & Drivetrain

6L80E Transmission Specs and Identification

6L80E Transmission Specs and Identification - Gearstar

The arrival of 6L80E transmissions – or Hydra-Matic 6L80 transmissions – on the automotive scene in 2006 showcased the considerable design change of the automatic transmissions that General Motors created. Before now, every transmission produced by General Motors was practically based on hydraulic controls. But they kept receiving new electrical elements from time to time as they modernized.

However, the 6L80E transmission was developed from scratch as an electric over-hydraulic transmission, complete with microprocessor control, and used extensively in trucks. Now, being more than 25 years since the last non-electronic transmission produced by General Motors, the 6L80E is recognized – otherwise referred to as the 6L80.

General Motors created this transmission to make the organization meet the demands of CAFÉ regulations on their automobiles. This 6-speed automatic, longitudinal transmission utilizes more gearing that keeps your vehicle running longer within its power band, significantly boosting the miles per gallon (MPG) of the car between 4 to 7 percent over the previous generation’s 4-speed transmissions.

But, of course, this depends considerably on the configuration of the vehicle the transmission is in. The 6L80E replaced the 4L60E in several vehicles, especially from the 2006 model year. It was primarily found in large cars powered by V8 motors. The 8L90E transmission may have phased out this automatic transmission, but it is still in production. Some of these vehicles in which you will find the 6L80E automatic transmission include:

6L80E Transmission Specs

The 6L80E automatic transmission is robust and capable of handling lots of power. It is known to handle a total gross vehicle weight of up to 8,600lbs, making it one of the greatest transmissions for LS swaps with zero modification required. The input torque rating of this transmission is 440lbs. As you may have already guessed, this transmission is primarily designed for rear-wheel drive vehicles only. It comes with a line pressure tap integrated only for diagnostic purposes.

6L80E Transmission Gear Ratios

The 6L80E automatic transmission makes use of 4 underdrive gears as well as two overdrive gears. As a result, it doesn’t have the usual direct 1:1 ratio like the 4L60E and 4L80E transmissions. Here is the gear ratio of the 6L80E automatic transmission:

  • First gear — 4.027
  • Second gear — 2.364
  • Third gear — 1.532
  • Fourth gear — 1.152
  • Fifth gear — 0.852
  • Sixth gear — 0.0667
  • Reverse — 3.064

The 6L80E transmission’s RPO code is ‘MYC’ and is manufactured domestically in GM’s Michigan plant. It employs a direct clutch-to-clutch shifting with zero bands.

6L80E Transmission Identification

You can identify the 6L80E in two unique ways. However, your identification method depends primarily on whether the transmission is still mounted in the vehicle or has been dismounted. If the 6L80E transmission is still mounted in the vehicle, you can only identify it using its RPO tag in the vehicle’s glove compartment. This is why knowing the RPO code for the transmission you want to identify is nothing short of golden. For instance, here’s a list of GM transmission RPO codes you should know, arranged in no particular order:

  • 6L80E — MYC
  • 6L90 — MYD
  • 4L65E — M32
  • 4L60E — M30
  • 4L80E — MTI

You will always find one of these sheets in the glove compartment of modern GM vehicles. Get hold of one and use it to confirm the identity of the transmission in that particular vehicle. But suppose the transmission has been dismounted from the vehicle. In that case, you will quickly recognize the 6L80E automatic transmission since it has an 18-bolt case, which is considerably more than any other automatic transmission from General Motors.

6L80E and 6L90 transmissions are almost identical and interchangeable for all practical purposes. However, the 6L90 transmission has several internal upgrades and a beefier set of gears. This is why using the pan gasket is considered the easiest way to identify or tell most General Motors transmissions apart. The major automatic transmission that the 6L80E will be confused for all come with different numbers of pan gasket bolts.

Therefore, ensure to count the pan gasket bolts carefully. The torque converter with the 6L80E transmission is a fluid turbine drive. In addition, it features a lock-up pressure plate for direct mechanically-coupled driving from the engine crank, just like those found in the 6L80E’s predecessor transmissions, such as the 4L80E, TH350C, 4L60, and 700R4 transmissions.

Differences Between 6L80E and 6L90E Transmissions

The 6L90E succeeded the popular 6L80E. The former is primarily designed to transform the extra torque efficiently. The 6L90E transmission was essential as new automobiles with more significant performance were required to hit the market. The most significant difference between the 6L80E automatic transmission and its successor, the 6L90E transmission, can easily be traced to its internal components.

Starting with their case: the case of the 6L90E transmission is shorter than its predecessor. The primary reason for this unique design was to enable this transmission to accommodate additional physical gear assemblies adequately. Owing to this, this automatic transmission permits two extra pinion gears, which equates everything to six. This essential modification is vital for high RPM and high torque figures.

However, this also resulted in a biggish shaft to ensure 100 percent reliability, which is more noticeable during loaded 3-4 upshifts where the shaft experiences enormous stress. More than a few applications came with several clutches peppered across multiple clutch packs in the automatic transmission. This significantly boosts the load capabilities of the clutch packs within the gears to which they are applied readily.

Conclusion

So, there you have it: the glorious specs of the high-performance 6L80E automatic transmission and its identification characteristics. The 6-speed, longitudinal automatic transmission powers several GM trucks and a wide range of vehicles alongside its successor, the 6L90E model. You should have no trouble recognizing the robust 6L80E in a lineup of identical transmissions.

In Transmission & Drivetrain

Rebuilding a Faster, Better TH400 in Almost Every Way

Rebuilding a Faster, Better TH400 in Almost Every Way - Gearstar

Rebuilding a transmission, such as the TH400, is not relatively as easy as changing your car filter or making an oil change. It is a challenge that will take a good mechanic almost all weekend. But if you don’t possess the skills of a mechanic, you shouldn’t attempt rebuilding your transmission. It is highly recommended that you leave this project in the hands of professionals. Here’s what you need to know about TH400 transmissions and how to rebuild them for faster and better performance.

Overview of TH400 Transmission

The TH400 transmission – or Turbo 400 transmission – was General Motors vehicles’ brainchild in 1964. This transmission was designed to substitute the ST300 2-speed automatic transmission. The TH400 transmission was used in Pontiacs and Cadillacs in the first year but somehow found its way to Chevrolets, Oldsmobiles, and other models by 1965.

The TH400 transmissions from 1965 to 1967 featured a mechanical device known as a variable pitch stator. This feature helped the torque converters characters in the transmissions and can easily be identified by the 2-prong plug on the case. By the time the ’70s arrived, the TH400 transmission was already used in heavy-duty GM trucks in 2WD and 4WD versions. 

In 1990, this transmission changed from TH400 to 3L80, resulting in longitudinally positioned 3-speeds and 8,000lbs. GVW or Gross Vehicle Weight. This name change was necessary as it made readily identifying the transmissions easier. This was also the year an early introduction of the 4L80-E transmission, the successor of the Turbo 400 Transmission that has overdrive, was made.

The TH400 transmission is an electronically-controlled, heavy-duty version of a TH350. The Turbo 400 Transmission required a kick-down switch by the gas pedal to inform the transmission when to kick down a gear. Military and heavy-duty GM vehicles still use this transmission as it is still produced today.

Features of the TH400 Transmission

The Turbo 400 transmission is a highly durable gear mechanism that offers improved performance over its predecessors. One common feature of the TH4oo transmission is its iron and aluminum construction. In addition, it has three tail shaft lengths and bell housing integrated into the transmission.

  • First gear – 2.48:1
  • Third gear – 1:1
  • Reverse gear – 2.08:1

The TH400 transmission weighs 135 pounds minus the fluid.

Identifying the TH400 Transmission

The Turbo 400 transmission has a main cast aluminum case measuring 24-3/8 inches long. This aluminum case is smooth. The rear mounting face of this transmission showcases a bold hex pattern with several ribs that run forward longitudinally. The shape of the fluid pan is somewhat irregular, likened to a distorted Texas pattern. The TH400 transmission is admittedly the largest of the regular General Motors transmissions.

Nevertheless, it is surprisingly compact, considering the immense power it can handle. General Motors created two significant variants of the Turbo 400 transmission. The first variant, i.e., the TH375 transmission, was made public from 1972 to 1976 in smaller displacement vehicles. It was used extensively in several small vehicles and easily identified by the ‘375-THM’ lettering carefully etched on the bottom or underside of the tail housing.

The other variant of the Turbo 400 transmission was the TH475; a heavy-duty transmission used extensively in large trucks from 1975 onwards. You can quickly identify the Turbo 400 transmission by checking out its kick-down assembly. This transmission uses an electric slide switch that controls the throttle linkage mechanism. On the other hand, the TH350 transmission uses a mechanical relay or cable kick-down mechanism attached to the throttle linkage.

Rebuilding the TH400 Transmission to Your Engine

The TH400 transmission is respected and loved due to its versatility and durability. However, there will come a time when the old transmission shows signs of wear and tear. Even the best transmissions are rebuilt at one point or the other. Wholly and correctly rebuilding an automatic transmission like the TH400 is ordinarily not beyond the capabilities of the average DIY automotive enthusiast. But there is always something that keeps away even pro automotive mechanics or technicians when rebuilding an automatic transmission.

Some claim not to have the necessary tools, while others say they don’t have enough time to carry out the task, so they whisk off the tranny to a specialty shop. As mentioned earlier, rebuilding a transmission is not an easy task. But the truth is that most of the tools required are standard hand tools. If you are not 101 percent sure of what you’re doing, best leave this task to professional mechanics. In this light, here are some of the tools required for rebuilding your TH400 transmission:

  • Safety equipment (eye protection, nitrile gloves, heavy-duty gloves, hearing protection, etc.)
  • Wrenches and sockets
  • Screwdrivers
  • Spring compressors
  • Snap ring pliers
  • Measuring devices
  • Pans for small components
  • Case holding features
  • Work surface
  • Busing removers and installers
  • Cleaning cases, etc.

When racing a Turbo 400 transmission, it is crucial to upgrade the direct and forward drums. The key revolves around more durable and stronger components and boosting efficiency for better performance, safety, and consistency. You can get a radical edge over other users by upgrading your TH400 to maximize drum function with unique configurations of more robust and lighter components. This development significantly boosts the efficiency and performance of your TH400 transmission for more power to the ground and stability/traction on the shifts.

Conclusion

The Turbo 400 – or TH400 – transmission is one of the automotive industry’s most widely used and versatile performance transmissions. This remarkable transmission has proven to be capable of handling massive power and is incredibly adaptable. This is not evident only in General Motor applications but also adapted behind Chrysler, Ford, and other engines.

You can maximize the reliability and performance of the TH400 transmission to make it deliver that exceptional result you trust at any power level. However, unless you are a certified mechanic or technician, it is highly recommended that you allow pros to handle the rebuilding of the TH400 transmission on your behalf.

In Transmission & Drivetrain

A Detailed Look at Today’s High-Performance Automatic Transmission

A Detailed Look at Today's High-Performance Automatic Transmission - Gearstar

If your AT experience in sports and muscle cars is limited to the three- and four-speed slushboxes of yore, let us say this: today’s high-performance automatic transmission is nothing at all like them.

The early dislike for automatic transmissions seems to have melted away. These transmissions were once inefficient, clunky, and slow as they often provided one less ratio than a manual transmission, even in the exact vehicle. However, cars with automatic transmissions became point-and-go machines since shifting their gears required zero human intervention. As a result, these automatic transmissions have made driving more manageable and have become widely available.

Transmissions are primarily designed to assist in moving a vehicle with minimal effort from its engine. As a result, automatic transmissions are very convenient, mainly when you are trapped in busy traffic situations where you must stop, start, and shift gears frequently. They are also excellent options for beginners, particularly when on an upgrade. Automatic transmissions also make a hill start incredibly easy while giving you all the freedom you desire from the clutch. The computer system in a vehicle is the only entity whose complexity surpasses that of transmissions.

Why a High-Performance Automatic Transmission?

Have you ever wondered why some transmissions are referred to as ‘high-performance’ transmissions? It is because high-performance automatic transmissions are much more carefully engineered and built for engines capable of speed and exceptional performance. There was a time when this gear mechanism was limited to only a few vehicles. These vehicles were typically used only for street racing or racing on the drag strip. But this line has been blurred over the years, and many cars now have high-performance automatic transmissions.

Gone are the days when numerous car enthusiasts reserved specific vehicles for drag or street racing. Instead, they have gone out of their way to outfit their unique daily drivers to make them adaptable enough to conform to numerous everyday roles. In other words, it implies modifying their existing muscle vehicles to meet their objectives: a dependable daily driver and a reliable tear-up-track or tear-up-the-street vehicle by night or on weekends.

Types of Vehicle Transmissions

Three primary transmissions exist automatic, manual, and electric. Both automatic and manual transmissions have service intervals. However, since they are sealed units, electric transmissions don’t have service intervals. Modern paddle-shifted automatics, especially those with up to 10 gears, usually post better acceleration numbers than manuals. 

Understanding Automatic Transmissions

The automatic transmission delivers torque from the car engine to the wheels, providing optimal power for negotiating numerous driving conditions. Both automatic and manual transmissions offer a fixed number of gear ratios. In contrast, a CVT (continuously variable transmission) theoretically gives an infinite number of gear ratios within a specific fixed range. You can achieve this in vehicles with manual transmissions by selecting the right gear, though this depends significantly on the prevailing driving conditions.

But on the other hand, automatic transmissions select the ideal gear ratio without human intervention. Manual transmissions require maintenance from time to time and must be checked during periodic service. However, manual transmission issues can usually be fixed or repaired without fuss. But continuously variable transmissions and automatic transmissions are comparatively maintenance-free, according to most vehicle manufacturers. 

Improving the Reliability of Your High-Performance Automatic Transmission

There are six ways you should consider if you want to improve the reliability and performance of your automatic transmission. They are as follows:

1. Service Your Automatic Transmission

In an ideal case, automatic transmissions last between 300,000 km to 400,000 km. As a result, most vehicle manufacturers claim that their automatic vehicles do not need transmission fluids. Therefore, you don’t need to change your vehicle’s transmission fluid unless you have a leak. But practically, as with most things in life, things are not all that smooth with the majority of automatic transmissions.

Most automatic vehicles will notice strange transmission-linked symptoms, especially after approximately 150,000 km. Servicing usually helps fix or prevent these issues. However, according to most vehicle manufacturers, there is no need for transmission fluid changes. But in reality, the essential properties of transmission fluid usually start deteriorating with time or age. This means changing your automatic transmission’s fluid would be necessary.

Saving the automatic transmission is always easier during the early stages. But there’s no harm in undertaking a transmission fluid flush later. In most cases, changing the transmission fluid restores its performance to a greater extent, whether or not the symptoms are acute. However, there is no 100 percent guarantee, but the transmission fluid change often works. This is an excellent and inexpensive way of fixing automatic transmission issues.

This is because a brand-new transmission costs nearly ten times the amount it would take to flush your transmission fluid. Therefore, attempting the repair makes sense. Although it won’t restore the automatic transmission to its full initial performance, some symptoms may suddenly disappear while others get less dramatic. However, it is highly recommended to maintain automatic transmissions during the early stages than to risk this occurrence.

2. Change Your Driving Habits

Always allow your vehicle’s engine to warm up for several minutes before you shift into drive. This is crucial, especially during the winter months.

3. Change Your Transmission Filter

This depends on the model and makes of your car. Your vehicle’s automatic transmission may come with a filter that needs to be changed regularly. However, newer model vehicles don’t have transmission filters.

4. Never Change Gears While Your Vehicle Is in Motion

Ensure your vehicle stops completely before changing gears to ‘reverse’ or ‘drive,’ or vice versa. If you don’t, you unnecessarily put a strain on your automatic transmission. This could result in severe issues down the road if you keep this up for an extended period.

5. Always Use the Recommended Type of Transmission Fluid

Consult your car’s owner’s manual to determine your vehicle’s ideal type of transmission fluid.

6. Service Your Engine’s Cooling System

The job of your vehicle’s cooling system is to prevent the engine from overheating. But only a few car owners know that the cooling system also cools the transmission fluid pumping through the gearbox. It is far more likely to require a transmission repair before your car engine overheats. Therefore, ensure your cooling system is in ideal condition.

Final Takeaway

Automatic transmissions are taking over the day as manual transmission dies out slowly. These transmissions were once inefficient, clunky, and slow but have become the point-and-go machines we know today. In addition, these automatic transmissions have made driving easier and have become widely available. You can improve the reliability and performance of your automatic transmission by following the tips highlighted above.

In Transmission & Drivetrain

C6 Transmission Upgrade Tips, Tricks, and Tech

C6 Transmission Upgrade Tips, Tricks, and Tech - Gearstar

Have you ever wondered if it’s possible to upgrade your C6 transmission to meet modern-day expectations in terms of toughness and performance? Yes, it is likely because experts have done it. You can revamp – or purchase a C6 performance transmission – rebuilt to handle anything you throw at it. Bear in mind that the C6 was built to provide long-term durability. As a result, it came to the fore in the powerful Ford trucks of the ’70s and high-performance Mustangs and sedans. This means you will get more than decent results if you upgrade your C6 transmission to meet modern-day standards. However, you may need to fish out some powerful components that will help take your C6 a little further to ensure you enjoy the best horsepower. Here’s what you need to know about the C6 transmission and a few upgrade tips you should consider.

Overview of the C6 Transmission

The Ford C6 transmission is the Ford Motor Company’s brainchild and prevailed from 1966 to 1996. It is a beefy 3-speed, heavy-duty automatic transmission heavily marketed as the SelectShift Cruise-O-Matic by Ford. This automatic transmission had a 30-year service life, after which Ford released it to give room for the modern overdrive versions of the company’s extensive transmission line-up. The C6 automatic transmission is somewhat lighter and has a less complex build than its predecessors. As a result, it offers less power loss and greater torque capacity, especially compared to its immediate predecessor’s MX transmission. The design of the MX transmission fooled many users, but the C6 achieved enormous capabilities with its more petite build.

Moreover, the C6 automatic transmission is simpatico to the Borg-Warner flexible shift band. The primary goal of making the C6 compatible with the adjustable shift band was to boost its durability and service life significantly. Despite the delivery of this purely mechanical – i.e., zero electronic controls –automatic transmission, it has a downside worth noting. First, it is beefy, meaning it weighs quite a lot. This causes valuable horsepower to be lost to turn the pieces and parts. However, this is gradually changing due to the possibility of merging customized components with specified C6 parts and particular pieces of the modern-day 4R100 electronic-overdrive sibling. The outcome is a powerful transmission unit capable of withstanding any abuse while negating the power-robbing pickles of the original C6 automatic transmission design.

C6 Transmission Gear Ratios and Vehicle Compatability

The stock C6 transmission from the factory features the following gear ratio:

  • First gear = 2.40:1
  • Second gear = 1.40:1
  • Third gear = 1:1

A brand-new wide-ratio gearset is installed, which offers a numerically more excellent gear ratio viz:

  • First gear = 2.72:1
  • Second gear = 1.54:1
  • Third gear = 1:1

This higher first gear is of much assistance with heavier vehicles since it makes the rear gear behave larger without unnecessarily boosting the highway cruising rpm. Some of the vehicles with the C6 automatic transmission include:

  • 1964 — 1970 Ford Fairlane
  • 1966 — 1974 Ford Galaxie
  • 1966 — 1980 Ford LTD
  • 1966 — 1979 Ford Thunderbird
  • 1966 — 1979 Ford Ranchero
  • 1966 — 1969 Ford Mercury Comet
  • 1966 — 1979 Ford Lincoln
  • 1966 — 1972 Ford Mercury Meteor
  • 1967 — 1996 Ford F-Series
  • 1967 — 1973 Ford Mustang
  • 1967 — 1978 Ford Mercury Cougar
  • 1968 — 1976 Ford Torino
  • 1977 Ford Mustang Cobra II

Therefore, upgrading your C6 automatic transmission should be part of your plans if you own any of these classic vehicles. Thus, it is essential to equip your C6 to combat common transmission problems.

C6 Transmission Upgrade Tips and Tech

Nothing should dampen the joy of driving a classic car on modern roads or cruising around town. But you can only guarantee this when you upgrade your C6. Therefore, here are a few tips that will come in handy when upgrading your C6 automatic transmission:

Modify the Parking Pawl Gear

Several small details of the C6 automatic transmission can be upgraded. This includes the modified parking pawl gear. In addition, it can be machined down such that it fits a needle-bearing assembly rather than a thrust washer. When the parking pawl gear accelerates, it pushes outward. This is entirely satisfactory until you ease off the gas pedal and go to deceleration. Switching to a needle bearing keeps the case from getting worked over on deceleration. At this point, the input shaft exerts lots of pressure on the housing. Modified parking pawls prevent severe damage from the strains that deceleration causes.

Replace the Planetary Gearset With a Stronger Counterpart

The First and Reverse planetary gearset in a C6 automatic transmission feature a 3- or 4-pinion unit. Each of these is constructed with aluminum. This is replaced with a 6-pinion, super heavy-duty steel planetary gear set. The extra pinions help to efficiently disperse the load since the steel material is more robust than its aluminum counterpart.

Work on the Lincoln Drum

The Lincoln drum refers to the Third-gear/direct drum featuring a higher snap-ring groove. This groove gives room for the installation of more clutches. A factory-fitted Lincoln drum uses four clutches, while the other third-gear drums only have three clutches. However, you can fit up to 6 brand-new high-performance clutches within the Lincoln drum for an enhanced grip.

Upgrade the Valve Body

You can get experts to upgrade the valve body, which allows for manual action (reverse and forward) or automatic shifting. In addition, you may require a valve body shift kit that promises to give firmer shifts to do away with annoying issues like clutch chatter, band failure, and a premature clutch. Drag racers can also install a trans-brake while settling for a deeper oil pan (optional) or using thicker high-performance bands.

Work on the Aftermarket Clutches

You can do away with stock clutches and go for less thick but highly durable aftermarket options. For example, stock clutches are usually 0.0080 inches wide. But you can find aftermarket options that are not thicker than 0.0065 inches.

Shifting Into High Gear

These are just a few tips you should consider and follow for upgrading your beloved C6 automatic transmission. This exercise ensures your transmission attains the level of performance its modern-day counterparts are accomplishing. The C6 automatic transmission already has a pretty solid foundation; all you need to do is to work on the suggested areas, and you’ll be good to go!

In Transmission & Drivetrain

6L80 vs 6L90: Devil’s in the Details

6L80 vs. 6L90: Devil's in the Details - Gearstar Performance Transmissions

The 6L80 and 6L90 are two of the most popular rear-wheel transmissions from General Motors. So many things have been discussed about these remarkable transmissions. This is especially true since several of these units are malfunctioning and require rebuilding. It shouldn’t be surprising that the 6L80 vs 6L90 transmission units are reaching their prime age in the repair cycle. However, technicians constantly need to rebuild these units across the country primarily due to a lack of appropriate attention to detail. Friedrich Wilhelm Nietzsche states, “the devil is in the details.” Here’s a quick look at the areas that must always be addressed when rebuilding a 6L80 vs 6L90 transmission.

6L80 vs 6L90 Differences

To know the differences between the 6L80 vs 6L90, it is expedient to check out each of these transmission units.

6L80 Transmission

The 6L80 transmissions heralded significant changes in the overall design of automatic transmissions fabricated by General Motors. All previous automatic transmissions by GM were based on hydraulic controls. These transmissions continually received electrical elements the more they modernized. But the 6L80 transmission was developed from the ground up as an electric-over-hydraulic transmission, complete with microprocessor control. The manufacture of the 6L80 began in 2005 and was released in most GM vehicles in the model year of 2006. The transmission lasted until 2016, available in 6L80 vs 6L90 versions.

6L90 Transmission

GM introduced a stronger variant of the 6L80 transmission within a year, known as the 6L90 transmission, RPO code MYD. This version of the automatic transmission is 1-3/8 inches longer than its predecessor, the 6L80, with approximately 25 percent of the internal components of the new transmission differing from the old variant. In other words, the 6L90 Transmission is a heavy-duty version of the 6L80 six-speed automatic. Engine torque rating increases to a minimal degree, but the output torque rating of this transmission jumps up by almost 220 feet per pound to 885 feet per pound.

In addition, the 6L90 transmission comes with a reinforced input gearset with two extra pinion gears, i.e., 6 in total, and a strengthened output gearset that utilized wider gears than its predecessor. The flexibility of the 6L90 transmission extends to the clutches as the latter has an additional clutch plate in every clutch than the 6L80 for heavy-duty applications. However, a 6L90 version lacks the additional clutch plate that can match application requirements where appropriate. The 6L90 transmission differed from its predecessor’s long-standing GM 32 spline specification output shaft to efficiently handle the significantly increased output torque capacity.

Instead, it went for a large diameter of 29 splines for most truck applications. But some HD trucks and 2WD van versions had a 36 spline. This is why it is essential to be mindful of your output shaft version before you proceed with any adaptation. As mentioned earlier, the 6L90 transmission shares up to 75 percent of its components with its 6L80 counterpart. However, the case of the 6L80 transmission is 35mm longer than the case of the 6L80 transmission. Moreover, the 6L90 transmission case accommodates additional fasteners between the transfer case and the transmission for enhanced driveline vibration/noise performance.

6L80 vs 6L90 Damage Differences

The 6L80 vs 6L90 transmissions usually get damaged around the pump area. The defect is mainly attributed to a torque converter failure. Most machinists and DIY enthusiasts know that torque converter failure is the #1 issue that grounds these transmission units. A total of 0.o1o inches to 0.015 inches of material is removed from the bell housing and stator support to restore the surfaces on typical pump assembly repairs. In addition, the depth of the pump pocket is restored by removing material from the surface of the bell housing.

This precise dimension must be matched for proper slide and rotor clearance. Most mechanics remove just enough material to restore the pump pocket and then get rid of an equal amount from the surface of the pump to maintain OEM dimensions. Some processes also include removing some material from the surface of the bell housing-to-case. Most rebuilt 6L80 and 6L90 transmission units have approximately 100,000 miles on them. Nevertheless, unit clearance should always be checked and modified accordingly, anyway.

Signs of a Failing Torque Converter

The primary job of a torque converter is to prevent the vehicle from stalling when it comes to a stop. The torque converter also multiplies engine torque beneath acceleration to enhance pulling power. The torque converter is located between the transmission and the engine. One side of the torque converter bolts to a flexplate at the back of the engine, while the other side fits perfectly over the transmission’s input shaft. The entire torque converter assembly is composed of 5 primary components:

  • Turbine
  • Stator
  • Impeller
  • Front cover
  • Clutch

Here are the common signs you will notice when your torque converter goes bad:

Shuddering

The shuddering of a torque converter is a noticeable problem, resulting in vibration before or after the lockup of the torque converter clutch. If you drive an old model vehicle, you usually feel the vibration around 40 to 50 miles per hour when the clutch lockup occurs. But for late-model vehicles that gradually apply the torque converter clutch, the shuddering of this unit may occur at different speeds.

Overheating

When a converter clutch stays locked up, it can cause a significant increase in the temperature of the engine coolant. Likewise, a locked stator one-way clutch can cause your vehicle engine to overheat, especially under cruise conditions. In addition, a locked one-way clutch may cause the transmission fluid to get incredibly hot. This potentially leads to internal transmission damage.

Stalling

When the torque converter clutch fails to release, your vehicle may stall, especially when coming to a stop. The problem will feel like you’re driving a car with a manual transmission and stopping to engage the clutch after releasing the pedal.

Key Takeaways

The 6L80 and 6L90 transmissions were powerful in their heydays and were released in several vehicles. However, they are prone to damage usually caused by the failure of the torque converter. This has resulted in a consistent pattern of transmission failures across the country, as evidenced by tech specialists. Knowing the specifics of these transmissions makes it easier to rebuild them into long-lasting automatic transmissions that will perform remarkably well for extended periods.

In Transmission & Drivetrain

Bad Torque Converter Symptoms, Diagnosis, and Fixes

Bad Torque Converter Symptoms, Diagnosis, and Fixes - Gearstar

The torque converter is a complex, highly sensitive, and vital part of your vehicle. A hydraulic coupling transfers your engine’s power to the transmission. Torque converters can perform this function because they are filled with automatic transmission fluid. On a fundamental basis, the torque converter is an excellent alternative to the mechanical clutch in standard manual transmissions. This is because torque converters in perfect working conditions multiply torque at lower revolutions per minute (RPM). This allows for more power than is usually possible via simple fluid coupling. However, when torque converters go bad, it can be worrisome. This is why it is crucial to know bad torque converter symptoms. This will make diagnosing it easier, and proper steps can be taken to fix the issue.

Symptoms of a Bad Torque Converter

These are the symptoms you should take note of as they inform you that your torque converter may have gone bad:

Illuminated Check Engine Light

The transmission control module (TCM) monitors the operation of torque converters in modern vehicles. If this module notices an issue with the torque converter or control circuitry, the device immediately switches on the Check Engine Light. It will also rapidly store a DTC (diagnostic trouble code) in its memory. Some vehicles switch on a dedicated transmission light when there’s a torque converter problem.

Slipping between Gears

Automatic cars are designed to shift smoothly between gears. You can feel the seamless transition, especially when you step on the gas pedal or decelerate quickly. However, suppose you feel your vehicle slipping between gears when it shifts. If you experience difficulty staying in a particular gear or the shifting feels somewhat strange or rough, there’s a great chance you’re plagued with a torque converter issue.

Shuddering 

This is a relatively common torque converter issue that often results in vibration, usually before or after the clutch lockup of the torque converter. If you own an older automatic vehicle, you may notice this vibration when driving at 40 to 50 MPH, which is when lockup occurs. But if you drive a late-model car, the shuddering may occur at different speeds since these vehicles usually apply the torque converter clutch gradually.

Leaking Transmission Fluid

The transmission fluid is crucial to a torque converter’s overall health and performance, including the entire transmission system. Unfortunately, torque converter seals can get worn out or damaged over time. This makes them prime sources of transmission fluid leaks. If your transmission fluid starts leaking, you shouldn’t waste time or take chances. Something is wrong with your torque converter, and a professional must check it out as soon as possible.

Loss of Acceleration

Is your vehicle feeling more sluggish than usual, and acceleration is now a struggle? You could have transmission issues, and the torque converter is the most likely culprit behind it.

Overheated Transmission

Your vehicle’s transmission comes with a highly sensitive temperature gauge that quickly detects when the transmission is overheating. It warns you of this development so that a certified transmission professional can get your vehicle looked at as soon as possible. Your torque converter may fail, or internal damage may require urgent attention.

Weird Noises

There may be trouble if you suddenly notice a whining noise from your torque converter. This whining noise implies that the pump within the torque converter is no longer functioning as designed. The noise could imply that the blade assembly no longer receives enough fluid. This can cause everything to run together, which is not supposed to be.

Diagnosing a Bad Torque Converter

You don’t need a professional to diagnose torque converters issues. This is something you can do by yourself. However, you will need the professional assistance of a certified torque converter technician to confirm your suspicions and fix them as soon as possible. Follow these steps to diagnose the issue and listen carefully for unusual occurrences like shuddering, strange noises, slipping, etc.

  1. Start your vehicle and allow the engine to run for several minutes.
  2. Apply light pressure on the gas pedal a few times.
  3. Push the vehicle’s brake and shift the gear into drive.
  4. Shift through each gear slowly.
  5. Drive around the neighborhood and listen attentively for unusual sounds each time you accelerate.

These steps may appear simple, but they can distinguish between driving with a bad torque converter and a good one. It is also easy to confuse torque converter issues with transmission problems. This is where the professional assistance of a torque converter specialist comes in. A specialist knows what to do to check for torque converter problems.

Fixing a Bad Torque Converter

Fixing a bad torque converter may save you a few bucks, especially if it is so damaged that you need to replace it with a new one. However, fixing or replacing a bad torque converter is more cost-efficient. If you keep driving your vehicle with a bad torque converter, the latter will cause considerable damage to the components within your transmission. You will spend a lot of money fixing those issues and still fix or replace the damaged or bad torque converter. A stitch in time, they say, saves nine. Therefore, get your vehicle to the nearest auto mechanic shop and get the torque converter specialist to look it over. Share your suspicions with the professional, as this will make it faster for them to readily diagnose or confirm issues using special equipment.

Conclusion

You can avoid torque converter problems if you know the symptoms to watch out for. The most obvious signs have been highlighted above. However, if you notice any of them, it is high time you get your vehicle’s torque converter checked out by a certified and trusted specialist. The cost of fixing or replacing your torque converter should not be an issue, especially if you consider the severe damage it may cause to your transmission if you don’t fix it on time. Therefore, always watch out for these signs each time you drive your vehicle. As soon as you notice any torque converter trouble shared above symptoms, take the necessary action.

In Transmission & Drivetrain

Ultimate 700R4 Rebuild Kit Guide

Ultimate 700R4 Rebuild Kit Guide - Gearstar Performance Transmissions

“What 700R4 rebuild kit is right for me?” This is the question of a prospective rebuilder searching for the best 700R4 rebuild kit on the market. The 700R4 automatic transmission is 4-speed in Chevrolet and GMC cars and trucks. General Motors launched this automatic transmission in the early 1980s, an upgrade to the popular 3-speed TH350 transmission and the older models of rear-wheel-drive vehicles.

The primary aim of developing the 700R4 automatic transmission was to improve fuel economy in vehicles significantly. This aim was achieved successfully, thanks to the 30 percent overdrive in 4th gear it featured. In addition, the overdrive allowed pickup trucks and sports cars that came with it to be even more affordable to use or drive. The 700R4 transmission is featured in vehicles – including rear-wheel-drive cars and trucks – from 1982 to 1993. Here are some of them, arranged in no particular order:

GMC

  • Jimmy: 1982 – 1993
  • Syclone: 1991 – 1992
  • Safari: 1983 – 1990

Chevy

  • Blazer: 1982 – 1991
  • Camaro: 1983 – 1992
  • Corvette: 1982 – 1992
  • Astro Van: 1985 – 1992
  • Suburban: 1984 – 1992

Cadillac 

  • Brougham: 1990 – 1992
  • Fleetwood: 1990 – 1992
  • Limousine: 1990 – 1992

The last 700R4 transmission was produced more than 20 years ago. This shows that it has been around for some time and remains popular due to its adaptability and reliability. However, rebuilding a transmission from the ground up and for the first time can be daunting, especially if you’re not DIY-inclined. You must be 100 percent sure you possess the chops or skills to take on this challenging task. It starts with deciding or figuring out the primary goal of your 700R4 rebuild. For example, why do you want to rebuild your 700R4 transmission?

Do you want to save money and time by performing a basic repair so you can get back on the road as soon as possible? Vehicle owners do 700R4 transmission rebuilds for several reasons. First, your transmission may function remarkably well now; however, you are considering dropping it and doing a high-performance 700R4 rebuild to handle heavy-load situations. Some even perform in-depth 700R4 transmission rebuilds to eliminate any known OEM weaknesses. Whatever your reason for rebuilding a transmission, you need to be sure it is the right step.

What to Consider Before Starting the 700R4 Rebuild Process

You need to consider the following before embarking on your transmission rebuild process. Here they are in no particular order:

  • First, what year is the vehicle whose 700R4 transmission needs a rebuild?
  • Is the transmission unit damaged? What is the extent of the damage?
  • What hard components should you get before starting the transmission rebuild process?
  • Are molded rubber pistons in the transmission, or do they use piston lip seals?
  • Does your transmission unit make use of a bonded valve body plate?
  • Does your 700R4 transmission’s pump use an O-ring or wedge-style seal?

These are just a few questions/things to consider before embarking on your 700R4 transmission rebuild.

The 700R4 Rebuild Manual

A rebuild manual is essential, whether or not you have the necessary experience rebuilding transmissions. A rebuild manual showcases every intricate detail of the transmission you are working on. For instance, a different component may be located at another corner in a particular year. When it comes to standard transmission rebuild manuals, the ATSG Manual is a perfect choice. They have a 700R4 rebuild manual with brilliantly-sketched diagrams and top-notch information that helps ensure you are doing the right thing as you rebuild your 700R4 transmission. The standard transmission rebuild kit, known as the Alto PowerPack, comes with the following:

  • A new filter
  • High energy carbon band
  • Corvette Servo
  • Trans valve body separator plate

SA Design’s Builders and Swapper’s Guide

This extraordinary rebuild guide is ideal for a high-performance transmission rebuild. The guide is informal, making it easier for anyone to read and understand while wrenching on a vehicle’s 700R4 transmission unit.

Top Performance Transmission Rebuild Kits

Part of rebuilding a 700R4 transmission includes ensuring the unit is stronger and much more efficient than it used to be. The top performance transmission rebuild kit from B&M that helps generate more power includes:

  • High-performance materials
  • Made only for the 1987-1993 700R4 transmission in particular
  • Complete gasket set
  • High-performance springs and valves
  • Drain plugs
  • One-year warranty

700R4 Rebuild Kit With a Torque Converter

When choosing the appropriate torque converter for your unique application, several variables must be considered. You can re-order a stock converter if you only rebuild a 700R4 transmission. There is also nothing wrong with going for a torque converter with the same stall speed as your automobile had from the factory. However, if this is not the case, you will need to be incredibly careful when searching for a suitable torque converter for your vehicle. Modern LS-type engines make good power, but the stall does not have to be as extreme since the heads generate more power. This allows for a less aggressive cam profile, allowing the engine to retain decent bottom-end power efficiently.

700R4 Transmission Recommendations

Experts highly recommend replacing every friction material – e.g., band/clutches – and the filter when undertaking a 700R4 transmission rebuild. Moreover, OEM 700R4 transmissions come with several inherent weak points within the sun shell and the ¾ clutch packs. Therefore, ensure you make use of an aftermarket sun shell. Ensure you replace the front stator tube bushings, rear case, and pump body. Replace any other part that looks worn or scratched. After any transmission rebuild, you must always use a remanufactured or new torque converter. Also, don’t forget to install or rebuild a remanufactured valve body on every rebuilt transmission.

Conclusion

Rebuilding any transmission is not a walk in the park. The 700R4 transmission is one of the toughest today and has held its own for over 20 years. You can get the best 700R4 transmission rebuild kit, depending significantly on your budget and the power you want to put on the pavement.

In Transmission & Drivetrain

6L90E Transmission Specs and Identification

6L90 Transmission Specs and Identification - Gearstar

The 6L90E is a high-performance component suitable for handling as much as 700 horsepower. This 6-speed automatic transmission built by General Motors powers everything from family sedans to audacious muscle vehicles, SUVs, and pickup trucks, alongside the 6L80E model. The 6L90E transmission is primarily designed for rear-focused all-wheel drive and rear-wheel drive vehicles. This remarkable AT is paired with GM’s V8 Duramax and V8 Vortec VVT engines.

This is why the 6L90E transmission is commonly used in GM diesel and heavy-duty trucks, including the Camaro ZL1 and cargo vans. General Motors manufactured the 6L90E in 2006, primarily designed for AWD/4WD and RWD applications. The 6-speed automatic transmission has several features, the most notable of which is the clutch-to-clutch function with a wide gear ratio for maximum efficiency and performance.

Difference Between the 6L80E and 6L90E Transmission

The 6L90E transmission succeeded the 6L80E transmission and is designed to transform the extra torque of the previous unit. The 6L90E transmission was critical as new vehicles with excellent or more significant performance were needed to hit the market. The primary differences between the 6L90E automatic transmission and its predecessor, the 6L80E transmission, can be traced to the internal hard components. First of all, the case of the 6L90E automatic transmission is shorter than its successor.

The reason behind this design was to enable the transmission to sufficiently accommodate extra physical gear assemblies. As a result, this transmission permits two additional pinion gears, equating everything to six. This critical modification is highly crucial for high torque and high RPM figures. In addition, this resulted in a large intermediate shaft to ensure 100 percent reliability, especially during loaded 3-4 upshifts where the shaft experiences great stress. Some applications came with many extra clutches across multiple clutch packs within the transmission. This increases the load capabilities of these clutch packs in the gears to which they are readily applied.

6L90E Transmission Specs and Ratios

The 6L90E automatic transmission provides optimum efficiency and 6-speed performance by taking full advantage of a much wider gear ratio instead of the conventional planetary gearset design. It has a die-cast aluminum casing with maximum input torque of 531 lb.-ft. and weighs approximately 245 lbs. with a torque converter and ATF. The 6-speed automatic transmission has a stall ratio of 1.9, a max shift speed of 6,200 rpm, a max GVWR of 15,000 lbs., and 29 spline output/shaft. It has zero PTO provisions and fluid capacity, approximately 13 quarts.

Gear Ratios

  • First gear: 4.027 to 1
  • Second gear: 2.364 to 1
  • Third gear: 1.532 to 1
  • Fourth gear: 1.152 to 1
  • Fifth gear: 0.852 to 1
  • Sixth gear: 0.667 to 1
  • Reverse: 3.064 to 1

This 6-speed automatic transmission is much larger than its predecessor, the 6L80E transmission, and features at least one more clutch plate in every pack than the 6L80E. This 6L90E transmission showcases a modular transmission case design that readily accepts numerous output shaft adapters and bell housings. This enables the transmission to be employed in various applications without requiring extensive modifications. It also doesn’t require complete application-specific transmission designs.

Features of the 6L90E

The 6L90E automatic transmission is electronically controlled and comes with a 300 mm torque converter. In addition, it is integrated with haul/tow settings that provide alternative shift schedules for high load conditions and decent speed control features. The heavy-duty version of the 6L90E automatic transmission has one additional plate in every clutch pack. This is necessary for stronger output/input gearsets. In addition, the modular design of this 6-speed automatic transmission makes for easy integration between a wide variety of engine applications. As with all transmissions, service intervals for the 6L90E transmission require changing the filter and fluid at 100,000 miles under normal or standard service conditions and at 50,000 miles under severe service conditions.

Common Defects of the 6L90E

The 6L90E has never been considered terrible when it comes to specification. Nevertheless, it has a few inherent design flaws that are worth mentioning. The well-known issues the 6L90E transmission has included:

  • Randomly popping out of ‘park’
  • Not shifting out of ‘park’
  • When in ‘reverse,’ it makes a loud rattling sound

The primary source of these issues is the plucking rod actuator assembly, which is notorious for its failure. Unfortunately, moisture also finds its way into the transmission’s casing and destroys the components that keep your vehicle functioning smoothly. Other common problems associated with the 6L90E transmission include:

  • Torque converter engagement or disengagement problems.
  • Hard shifts to third or fifth.
  • Transmission fluid over temperature.
  • Flare or slip on the 2-3 shift.
  • Slip in third or fifth gear.
  • No reverse or slip-in reverse.

The most obvious sign that the 6L90E automatic transmission has issues is when the reverse gear is slipping or no longer engaging. If you’re experiencing any of these problems highlighted above with your 6L90E transmission, take your vehicle to a certified technician. The technician or mechanic will check out the transmission and make some recommendations, such as checking or leveling up the transmission oil, replacing the torque converter if it’s worn out, changing the gearbox oil, etc.

Which Vehicles Have a 6L90E Transmission?

As mentioned earlier, General Motors uses the 6L90E automatic transmission on various trucks, cargo vans, and passenger vehicles. The weight capacity and superb torque handling of the 6L90E transmission make it perform exceptionally well in construction, commercial, and industrial settings. The Chevrolet Express/GMC Savana, Chevrolet Silverado HD, and GMC Sierra HD pickups started using this model in 2007 and keep doing so even today. Unfortunately, this makes some of the common issues associated with the 6L90E automatic transmission much worse due to the high usage and payloads they usually handle daily.

The Bottom Line

The GM 6L90E is a high-performance gear mechanism for handling as much as 700 horsepower. It is a 6-speed automatic transmission that powers everything from a wide range of vehicles, including family sedans, audacious muscle vehicles, SUVs, and pickup trucks, alongside its predecessor, the 6L80E model. The 6L90E is not perfect in every sense, but it is capable enough to still be in use today in many modern-day vehicles.

In Transmission & Drivetrain

E4OD Transmission Upgrades for Heavy-Duty Towing and Off-Roading

E4OD Transmission Upgrades for Heavy-Duty Towing and Off-Roading - Gearstar

The E4OD transmission developed by Ford is a heavy-duty unit generally found in the Bronco, E-series vans, Expedition, and F-series trucks. This is a computer-controlled transmission designed for rear-wheel drive automobiles. Ford launched the E4OD in vehicles manufactured from 1989 to 1997, the well-known model years.

Identifying the E4OD Transmission

The popular F-series trucks and E-series vans with the E4OD transmission manufactured from 1989 to 1993 come with a shifter pattern of P-R-N-OD-2-1 and an overdrive cancel switch. But in 1994, Ford launched the 4R70W transmission that also employs a similar shifter pattern. Unfortunately, this similarity in the shifter pattern made examining the shifter to determine the vehicle’s particular transmission highly ineffective.

Ford engines in all 4.2-liter, 4.6-liter, and a handful of 5-liter make use of the newer 4R70W. But diesel-powered vehicles, as well as those equipped with 4.9-liter, 5.4-liter, 5.8-liter, 6.8-liter, and 7.5-liter engines, come with the E4OD. Another way of determining or identifying a truck’s transmission is by measuring the fluid pan. The ideal measurement of the E4OD is 20 inches in overall length, while on the contrary, the 4R70W is 15 inches in length.

Gear Ratios

These are the gear ratios for the E4OD transmission are as follows:

  • 1st — 2.71:1
  • 2nd — 1.54:1
  • 3rd — 1.00:1
  • 4th — 0.71:1

Computer-Controlled E4OD Transmission

The E4OD transmission was Ford’s top-selling electronically-controlled automatic in light trucks. Receives commands from the EEC-IV engine control computer on board. This computer rapidly processes all engine, transmission, and vehicle inputs to determine the best and unique shift points for consistent shift feel and performance. Ford claims several factors determine the shift points of the transmission. These factors include:

  • Engine speed and altitude.
  • The transmission temperature.

Ford was able to salvage 25 percent much better fuel economy in the 1991 F-150 2WD pickup with the E4OD than the 1990 F-150 with the older C-6 transmission.

Recommended Upgrades

Ford’s 7.3-liter power stroke engine was known for its incredible power potential and durability. Nevertheless, the E4OD came on the scene fully equipped on Ford power stroke-equipped available vehicles of the mid-90s. The E4OD worked remarkably well in light-duty applications. However, its design was not tough enough to handle the exceptional needs of most Powerstroke-equipped trucks. Some aftermarket companies offer upgrade components to complete heavy-duty replacement transmission to improve the factory-made transmission significantly.

Aftermarket Modifications 

You can replace several components of the E4OD transmission with upgraded aftermarket parts. These include:

  • Torque converter
  • Transmission control module
  • Pressure regulator
  • Front pump
  • Rear case bushings
  • Sun gear
  • Clutch piston
  • Reverse boost valve
  • Sprags
  • Center support

Adding auxiliary oil coolers can enhance the E4OD to have more excellent reliability.

Essential E4OD Transmission Upgrades and Maintenance

You can enhance the life of your still-functional E4OD by installing a transmission cooler alongside fresh fluid and a filter change. Heat is the arch-enemy of a vehicle transmission, which can easily be compounded by the strain associated with plowing or towing. However, you can perform these simple upgrades without uninstalling the transmission. If you use your vehicle frequently for towing, check out the severe duty maintenance schedule highlighted in your owner’s manual to extend the life of your transmission.

You may also add an external filter so that the latter can work in tandem with the transmission’s internal filter. Upgrading your transmission may require the uninstallation of the gear system. But a pre-1988 E4OD will benefit the most from upgrading by installing the 7-tooth rear lube style rear output shaft. Of course, the truck would have to run a numerically-high rear axle ratio for this upgrade to work efficiently. Installing the output shaft prevents planetary gear failures that come about as a result of poor lubrication. In addition, if input shaft replacements using an aftermarket unit are performed, it will significantly boost shift quality and strength.

E4OD Transmission Reprogramming

The E4OD is an electronically-controlled gear system requiring reprogramming to minimize gear hunting and boost operation. You can bring down gear hunting by adjusting the torque converter lock-up point and line pressure. Aftermarket companies all over the country offer several user-adjustable standalone programming modules designed exclusively for the E4OD transmission. Aftermarket E4ODs also come with unique design elements, such as well-designed transmissions that don’t usually have the general weaknesses plaguing those which are factory-designed. Ensure you only work with a highly reputable aftermarket company when the time comes to rebuild your transmission.

  • Heavy-duty valves.
  • High-quality gears.
  • Superior ball-bearing construction.
  • Magnificent clutch packs.

The price of most aftermarket E4OD units is very close to the amount a rebuild would require. Therefore, do your research to find out how much it will cost you for heavy-duty replacing units before committing to a costly rebuild. You can also enhance cooling capacity by opting for aluminum transmission pans.

E4OD Transmission Overhaul

The primary goal of building an E4OD transmission is to accomplish these:

  • Maximum durability.
  • A minimum build-up of internal heat.
  • Enhance the crispness of overall delivery off and on the road.

E4OD Transmission Rebuild Tips

Keep these tips in mind for your E4OD rebuild:

  • Low reverse clutch. Make use of performance frictions as well as steels to obtain tighter tolerances. Ensure the clearance is between 0,020 to 0.040 inches when installing the low reverse frictions. This is to shorten the delay when going into reverse.
  • Rear planetary. If the three-pinion OE aluminum shows zero signs of wear, keep it. This particular planetary rarely causes any issues. However, you may replace this planetary – if in doubt – with a six-pinion steel version used extensively in the power strokes.
  • Bushings and bearings. Replace all brass bushings showing wear and tear. You should also replace all the bearings.
  • Overdrive planetary. Convert/change the overdrive planetary into steel as the aluminum versions are known to split the neck.

The Bottom Line

Only a professional should handle upgrading your E4OD transmission for heavy-duty towing on and off the road. This is vitally crucial if this is your first rebuild.

In Transmission & Drivetrain

4L80 Torque Converter Basics for Reinforcing Speed and Drivability

4l80 Torque Converter Basics for Reinforcing Speed and Drivability - Gearstar

There was a time when drivability, low emissions, and high horsepower were topics of discussion and disputes. Nowadays, auto-shift cars feature speed, fuel economy, and power as vital features every car owner watches out for. These enhancements have also made it easier for car owners to abandon their gearshift. Nevertheless, selecting the correct torque for your automatic vehicle enables you to enjoy the full benefits of today’s technology. This is vital since the 4L80 torque converter links the engine to the transmission while tuning the connection to generate the most power while minimizing heat. Therefore, choosing the wrong torque converter can quickly thwart your dream of a dependable gear-banging since the reliability and power of drivability rely heavily on it. However, if you have plans to enhance your vehicle’s speed while getting excellent fuel mileage regardless of the shift pattern you’ve settled for, you have no choice but to fall right back to torque converter basics.

What Is a 4L80 Torque Converter?

A torque converter transmits an engine’s torque to the transmission. The transmission enables you to move the vehicle along the road. In simple terms, the torque converter connects the power source to the load via the transfer of rotating power from a prime mover to the rotating driven load. They are usually found in automatic transmission cars and efficiently replace the clutch system standard in manual vehicles.

How Does a 4L80 Torque Converter Work?

Transferring power from any powertrain to the transmission is a relatively complicated process. This is because several components move in synch at the same time. Of course, you know that you are just pushing the gas pedal with your foot, flipping a paddle, or moving a gearstick. But a lot goes on right under the floorboards. Each movement beneath the floorboard is carefully engineered and developed to allow for the seamless meshing of multiple components that propel your vehicle into motion.

In Manual Vehicles

A manual vehicle comes with a clutch assembly that gives rise to the connection and disconnection between the transmission and the engine, which drives the wheels. A throttle stop sets the idle of the engines, which signifies the minimum engine speed at which the engine can sit comfortably before it stalls as a result of a shortage of air/fuel mixture entering the cylinders. Without a clutch, the engine would stall when you slow your vehicle down to a stop because the transmission load would drag it far below its workable revolution limit. The clutch brings about the disconnection needed to keep the engine running smoothly and the re-engagement alongside some throttle to get the vehicle functioning again.

In Automatic Vehicles

However, in an automatic vehicle, no proper clutch exists. So instead, the clutch is replaced by a torque converter. The torque converter does the same job as a clutch: it allows the car engine to stay up and to run while the wheels and transmission slow down until they stop. But the torque converter goes about this assignment ingeniously and differently. The torque converter is also referred to as a fluid coupling, which transfers rotational energy via fluid movement from one automated system to another. The fluid coupling can replace the clutch because it can allow the car engine to rotate freely by significantly minimizing the torque delivery from the powertrain to the transmission. The torque converter never connects to the full, as you will feel via the ‘creep’ that occurs when you take off your foot from the brake of your automatic vehicle at a standstill.

A pump that transmits fluid all over the torque converter helps achieve torque control. But this depends significantly on the crankshaft’s rotation. A turbine rotates within the torque converter as the pumped fluid gets in contact with the turbine’s vanes. This gauges the torque that will make it to the transmission via the input shaft. The torque converter’s casing is connected to the flywheel, which also spins at the exact rate of the crankshaft. Within this housing are a stator, the impeller or fluid centrifugal pump, and the turbine. The stator is a barrier to flinging the fluid back to the turbine instead of behind the pump. This action significantly boosts the efficiency of the system. In addition, the impeller flings the transmission fluid into the turbine fins, which, in turn, spin rapidly and transmit torque through to the transmission.

4L80 Torque Converter Basics

Here are a few ways you can speed up your vehicle using torque converter basics:

Maintain Your Car With Premium Fluids and Filters

Using high-quality filters and fluids helps combat excessive heat. However, you must watch out for how much heat your vehicle produces, which could affect how long it services your needs.

Ensure Your Transmission Cooling System Is Adequate

A cooling system helps regulate your engine’s temperature to avoid or prevent overheating. Irrespective of the quality of torque converter you opt for, you need to give more priority to combatting heat. You must consider pairing a cooling system with a high-quality filter and fluid.

Provide the Technician With Thorough Detail About Your Car

Torque converters are not one-size-fits-all. Instead, several manufacturing companies specialize in designing torque converters to fit a particular vehicle’s use and the driver’s specific needs. These companies showcase tech lines that potential clients can use to reach out to them to offer as much information as required about the customized torque converter to be constructed. Information can never be enough at this juncture. But ensure you include essential information such as camshaft specs, engine size, rear-end gear, and tire size.

Make Use of a Lock-Up Converter

A lock-up converter becomes useful for increased fuel mileage, reliability, and driveability. In addition, it can significantly minimize the heating issues of transmissions due to too much slippage from a higher-stall converter. Lock-up converters usually come in an overdrive-style transmission. However, this converter also showcases a clutch that creates a near-direct drive effect when engaged. This helps reduce slippage to the barest minimum, regardless of the stall speed, which successfully helps combat the heat that may potentially destroy the transmission.

Choose Your Camshaft Wisely

Converters and camshafts have a close relationship and could play significant roles in choosing the ideal converter for your vehicle. Camshafts determine the powerband of engine combinations to a very great extent. For instance, a 2,000 – 2,400-stall converter is an excellent choice when considering a cam duration of 248 degrees. On the other hand, a 2,400 or even 3,000-stall converter is much better for a cam duration of about 268 degrees, etc. These values portray that you will need a torque converter with just the right amount of stall for optimum performance while preventing heat generation. An additional advantage is that your engine can sit ideal in gear, especially if you use a stock camshaft. This is why it is crucial to determine the ideal stall speed.

The Bottom Line

The basics of a 4L80 torque converter are highlighted above to ensure you have a unit ideal for your vehicle. In addition, you can determine if the camshaft in your car is the most appropriate one or if a replacement will be needed. Everything boils down to the crucial factors to consider when settling for a torque converter that will always make you enjoy each minute you spend driving on the road.

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