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Common Automatic Transmission Problems

The automatic transmission or transversely mounted transaxle of your vehicle is the most complex piece of mechanical engineering in the entire auto. Numerous circuits, check valves, and clutches have to work in synchronicity and exact pressures to actuate the smooth driving experience that Americans know and love. Because everything is so complex and relies upon precision, it is not uncommon for a problem to occur when gaskets leak, fluid wears thin, and parts wear out over time. Below, we have detailed 7 of the most common auto transmission problems that you may encounter.


Automatic Transmission Problem: Grinding or Shaking

If your automatic transmission is shaking when you shift, this could be a sign that the motor mounts are bad or of a bad torque converter. If the torque converter sticks, it will shake and shudder before it stalls out the engine at lower RPMs.

The motor and transmission mounts can lead to hard and jarring shifting, shaking at idle, and other noises when they are worn out. Grinding noise may emanate from a chipped gear, a cracked gear, or low transmission fluid.

If you find that your transmission is not shifting as smoothly as before, it is a good idea to first check for leaks by wiping a paper towel under the transmission housing and smelling for a telltale pungent odor of trans fluid. Open a bottle of it at your local auto store and take a whiff if there is any doubt. Trans fluid will usually look bright pink if your vehicle takes a Mercon type formula.

You should then check your motor mounts of damage like cracking, particularly the front motor mount which is usually hydraulic. The mount can become separated into two pieces with age as the rubber dry rots. You may also have vibration and hard shifts simply because the rubber itself has become very hard and dry rotted but not yet deteriorating into pieces.

And finally, you should note what gears that you experience the problem and what speeds. If there are particular gears that are damaged, you will only hear it when that gear that is chipped or cracked is engaged.


Automatic Transmission Problem:

Car Won’t Engage or Respond

When your auto box won’t even engage or respond at all, you most likely have burned out clutch packs, extremely low fluid, broken bands, or a problem with the valve body. It may also have pressure problems for some other reasons.

In some cases, there can also be a problem with the linkage. There are usually mechanical cables that are connected to the shift lever that may have slipped off the gear selector. In some models, this may not be the case, and there could be complex electronic reasons for the malfunction.

It is not common for a transmission to die out totally overnight. What usually happens is that you experience slipping that progresses and eventually leaves you with a transmission that revs like it is in neutral all the time. Transmission problems tend to creep up on you and may be caused, in this case, by a number of issues that require extensive diagnostic experience to pinpoint.

The valve body and electronics are another point that you may want to check. Any damage to the wiring or fragile plastic connectors that become brittle over time can cause the transmission to rev like it is in neutral when any gear is selected.


Automatic Transmission Problem:

Car Making Noises

If your transmission is just making noises and you aren’t sure what it can be, you should first inspect for any physical damage. You should note and analyze what triggers the noises and what they sound like. If you hear a whirring noise like an airplane roaring when you are driving at speed on the highway, this is most likely the wheel bearings and not the transmission.

An automatic hydraulic transmission isn’t prone to making noises because the clutch packs either activate or they don’t. While it is possible for a gear to chip or crack, this is rare. The torque converters can also break at certain spots and lead to noises but, again, very rarely. If the noise is during shifts, and your experience hard shifts, this fits more within a motor mount issue.

When a transmission does whine, it is usually the differential that needs gear oil replacement or because the transmission itself has deteriorated its fluid too quickly from running heavy duty cycles in hotter than usual conditions. This can happen after a leak, in fact.

If you have less fluid to lubricate, the transmission fluid can start to run hot and volatilize quicker. Because many transmissions today are sealed units that boast of lifetime fluid, you will need a specialist to fix the problem if you don’t see a dipstick to check the fluid levels.


Automatic Transmission Problem:

Burning Smell

As stated, transmission fluid that gets too low can overheat and burn up in a process called volatilization. If you find that the gasket is bad and that the fluid residue on it has a musky Mercon smell, you should act fast to have your level checked. A fluid level should be checked with the car running and in neutral. You simply set the emergency brake and check the fluid level with the dipstick if one is available.

The method for checking the fluid level in sealed transmissions involves jacking up the vehicle evenly, as if on a lift, and filling the fluid with a certain amount. Then, only when the internal temperature sensor is at the right temp on the computer diagnostic interface can you remove the fill plug and let the excess fluid out.

You really need the highly technical factory manual instructions to do this job correctly. You don’t want to mess around with automatic transmissions or use the wrong type of fluid. It is not hard to burn out a transmission entirely. Because an auto trans is one of the most expensive things on your vehicle to replace, it should never be taken lightly.


Automatic Transmission Problem:

Gears Slipping

As stated, the gears often slip when the clutch packs deteriorate and the bands wear out. It can also be caused by sticky fluid gumming up the valves in the valve body, however. This occurs because the valves are made of a special thermal plastic that expands as it heats up.

If the filter is dirty and the fluid is dirty, little particles can jam up the valves and cause slipping because it takes more time and pressure for the gear to finally activate the clutch pack and respond.


Automatic Transmission Problem:

Low or Leaking Fluid

As previously stated, all these issues are interconnected and often have a lot to do with leaky gaskets. That is where it all starts in many cases. You can check the fluid level and for leaks as described above.


Automatic Transmission Problem:

Check Engine Light

A check engine light will illuminate in many situations. It depends how sensitive the diagnostic sensors on your vehicle may be, however. You can expect a check engine light for things such as solenoid wiring problems, bad solenoids, torque converter hydraulic circuit issues, and other electronic issues.

If the TCM (transmission control module) is bad, you won’t be able to get any codes out of it. And, most likely your car will not even start because the ECU (engine control unit) needs a signal from the TCM to start.

Decoding the meaning of the Diagnostic Trouble Codes that may be stored on the ECU or TCM is an art all in of itself that requires expert technicians with years of experience to add up all the pieces of the puzzle.



Don’t let subtle running issues go. Most transmission problems can be caught early and corrected if you listen to your vehicle and act when something doesn’t feel right. The longer you a let a problem go, the greater the risk of damaging other components beyond repair. Most transmissions can’t be repaired and need to be replaced if it is not a simple wiring, fluid, mount, sensor, or linkage adjustment issue.

Ensure that shop that you go to specializes in the procedure and that they are fully insured and experienced enough to work on your vehicle. For more information, you can contact us or call 318-742-7754.


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Transmission Spotlight: Powerglide Transmission


Throughout the history of automobiles, manufacturers have tried to improve on transmission operations. In 1940, General Motors implemented the first version of the automatic transmission. Named Hydramatic, it was initially placed in that year’s model Oldsmobile.


A Transmission Shift

After World War II, car manufacturers took the knowledge they gained and put it to use in their commercials vehicles. At the start of the 1950s, General Motors put it to use in the next generation of an automatic transmission. This was one called the Powerglide transmission.


Two-Speed Transmission

The Powerglide was a two-speed transmission used for the low-end passenger cars and trucks under the Chevrolet brand. When the Hydramatic plant was damaged by fire in 1953, the Powerglide was placed in the company’s Pontiac and Oldsmobile models.


A Transmission for a Generation

The Powerglide transmission was the go-to for General Motors vehicles from 1950 to 1973. Though the company advertised this new version of the automatic as shiftless, it actually wasn’t. In the earliest models, drivers had to shift up one gear to gain maximum acceleration. In turn, the transmissions were quickly damaged as they were run too long before a gear shift.

In the 1960s, General Motors worked out the kinks. Soon enough, the Powerglide transmission became a truly shiftless operation. Thus, drivers no longer needed to worry when to properly move up a gear. In addition, when paired with V-8 engines, the shift between low and high gear felt seamless.


From Low-End to Muscle

With the transmission’s improvement, it became General Motors’ standard automatic until the three-speed TH350 was implemented in 1973. Some of the Chevrolet models to utilize the transmission included the Corvairs, Camaros, Corvettes, and Malibus.

The transmission wasn’t relegated to simply Chevrolet models. It was commonly seen in cars made by AMC and Fords. Over two decades, GM produced 17 million of this two-speed model.


Powerglides for Today’s Vehicles

Automatic transmissions have come very far since the invention of the Powerglide. Yet, that second-generation transmission is still used today. That’s due to its simplicity and lightweight construction. In addition, it allows for a variety of horsepower options.

Today, in combination with a low rear gear, this transmission is an option for quarter-mile vehicles used in drag races. In addition, because it’s less than 100 pounds due to its aluminum construction, the transmission is used in racing with high-performance engines.

This is due to the way the transmission is coupled. Instead of a mechanical coupling used in a clutch-driven gearbox, it uses a fluid coupling. This eliminates the bump or pop felt as transmissions are shifted into gear from neutral. In turn, this allows for an increased speed capacity. In fact, using this transmission with current turbo engines has resulted in speeds up to 260 mph.


Finding Powerglides

It’s not hard to find Powerglides today. An internet search provides numerous locations where these are sold or custom built. How much they cost depends on the amount of horsepower required and if installation is needed.


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Transmission Spotlight: 6L80E/6L90E


Here is a six-speed automatic transmission that has been developed by General Motors. Both the 6L80E and 6L90E models are designed for all-wheel-drive vehicles that are rear biased and have a longitudinal powertrain orientation. Both transmissions are meant to conserve fuel, and each is controlled via a six-speed automatic transmission that is a quality successor to the SL family of transmissions.


6L80E/6L90E Transmission Overview

The Hydra-Matic transmission has a modular design, and it shares some components that allow it to accommodate varying torque levels, engines, and applications. Each of the versions that have been developed has a unique gear set that is configured to allow for a wide range of ratios when compared to a more conventional type of gear set inherent with many automatic transmissions today. This enables the transmission itself to allow for great fuel savings, while at the same time permitting the vehicle to accelerate nicely.

General Motors decided on a modular concept for these transmissions in order to allow for common components to be able to be used interchangeably, thereby allowing for tools to be used during the manufacturing stage that allows for four variants within the six-speed family of transmissions. All of the versions on the market today use three gear sets. This includes one gear set that is a simple input planetary design, while two are output gear sets.

Some of the applications do allow for Performance Algorithm Shifting. This type of shifting can sense how assertively a driver is using the output of the engine in order to make a determination as to whether or not an upshift or downshift is necessary based on the engine speed. There is also a Driver Shift Control that will permit the driver to actually shift the transmission, similar to that of a gearbox that is clutches and manual. There are electronic safeguards built into to keep the driver from over-revving the engine in the event that the incorrect gear is selected by accident.

One other interesting component with these transmissions is the Advanced Control System. This is what allows the temperature to stay constant in comparison to a module that is mounted on the body. Since the transmission and the module are actually assembled at the same time and together, there are not any additional steps required during the assembly process for the vehicle.


6L80E vs. 6L90E

When comparing the two transmissions, it is important to keep in mind that the 6L90 is more heavy duty than the 6L80, even though both are six-speed automatic versions. The former also comes with a stronger input gear set. This has two more pinion gears, which gives it six in total. The output gear set on the 6L90 is also wider than the 6L80, giving it more flexibility. The 6L90 also has one more clutch plate that can match up with the requirements of certain applications when necessary.

It is interesting to note that the 6L90E transmission does share roughly 75 percent of the same parts as that of the 6L80E transmission. The case on the 6L90 is a bit longer, and it can make use of more fasteners for the transmission and the corresponding transfer case. This tends to lead to better drive performance and less noise and vibration.

Which transmission you end up choosing depends on your vehicle and your unique needs. If you need a bit more power, you might look at going with the 6L90E transmission. If that is not something you are after, the 6L80E transmission will likely suit you just fine. Both are built for performance, and they will each give the driver the power they need to excel on both long and short journeys.

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C6 Transmission Spotlight


The Ford C6 is a heavy-duty automatic transmission built by Ford Motor Company between 1966 and 1996. It was marketed as the “SelectShift Cruise-O-Matic.” Compared to its predecessor MX transmission, the C6 offered lower weight, less complexity, less parasitic power loss, and greater torque capacity for larger engines. It did this without exceeding the packaging dimensions of the MX. These design goals were in line with those of the C4 for smaller engines.

To cut down on weight and cost, the C6 featured a simple, three speed Simpson planetary gearset as well as over 10 lb (4.5 kg) of powdered metal. To increase shift quality and long-term durability, it became the first automatic transmission designed to use the Borg-Warner flexible shift band. The C6 also included disc clutch plates instead of bands on the low and reverse gears, including new composite plates and valves. This gave it the capability to handle upwards of 475 ft-lb of torque.

Prior to 1966, Ford FE and MEL big-blocks were fitted with cast-iron MX and FX 3-speed automatic transmissions. In 1966, Ford introduced its own heavy-duty C6 3-speed automatic transmission for high-torque applications behind large-displacement big-block V-8s. Although the C6 has a completely different case and external components than the C4, it is virtually the same internally to the C4—on a larger scale for heavy-duty use.

The C6 was produced with four basic bell housing bolt patterns over its long production life and is a very rugged transmission designed for high-power applications. The round six-bolt pattern is for FE-series big-block, which includes the 332, 352, 361, 360, 390, 406, 427, and 428 engines. There is another distinctive six-bolt bell housing pattern for the 429/460-ci 385-series big-blocks and the 351M and 400M Cleveland-based, raised-deck V-8s. The six-bolt pattern arrived to the C6 in 1968 with the 429/460 big-block V-8s. There’s also the small-block C6 originally intended for 351W and 351C engines, which fits any six-bolt 289/302/351W/351C small-block bell housing bolt pattern.

By the 1970s, Ford had a respectable lineup of modern lightweight automatic transmissions. An ironic footnote to this story is the weighty cast-iron FMX transmission, which remained in production until 1981 behind 351W small-block engines. It was an easy off-the-shelf solution for Ford, which needed the FMX to keep up with production demands when there weren’t enough C4 and C6 transmissions to go around.

Later, there was a C6 transmission produced for Diesel engines beginning in the 1980s, before the E4OD (4R100) was introduced in 1989. The long history of production really highlights this transmission’s reputation for durability. Despite the E4OD’s presence, Ford still continued to build the C6 up until 1996 for many commercial and industrial applications.

The C6 transmission is still very popular in the sport of drag racing today, with units equipped with manual valve bodies and transmission brakes. It is also widely used in off-road applications due to its reputation of being nearly indestructible. They are available in small block, big block or round bell housing depending on the motor you want to equip it with. We can custom build these to meet or exceed your expectations, check out our store to find out more.

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4L80E Transmission Spotlight

4L80E Transmission

The 4L80E was a series of automatic transmissions from General Motors designed for longitudinal engine configurations. It was a new model based on the design of the Turbo-Hydramatic 400, first produced in the year 1963. 4L80Es were initially only available in Chevrolet or GMC trucks, vans, and commercial vehicles, as well as the Hummer H1. It was also adopted by Rolls Royce in 1991 and modified initially for use in the Bentley Continental R, and later other Rolls Royce, Bentley, and Aston Martin luxury vehicles.

The 4L80 nomenclature denotes that the transmission is a 4-Speed, Longitudinally-mounted, and for 8000 lbs. vehicle weights. Maximum engine input torque for the 4L80 is 440 ft. lbs. and the maximum output torque is 885 ft. lbs. The case is die-cast aluminum and was designed for vehicles up to 16,500 lbs. It’s RPO code is “MT1″ and has been domestically manufactured in GM’s Ypsilanti and Willow Run plants.

The torque converter is a fluid turbine drive and like those on its predecessor transmissions; the TH350C, 700R4, and 4L60, the 4L80E features a lock-up pressure plate for direct mechanically coupled driving from the engine crank. The 4L80E also features a 310 mm torque converter. As to length, this transmission is 26-1/4” long. This transmission typically accepts a 6.3-quart fill and features a dry weight of 254 lbs. that can weight up to ~268 lbs. when full. Like some earlier automatic transmissions, the 4L80E features one line pressure tap available for testing and diagnostic purposes, and also feature transmission cooling ports for external transmission oil coolers.

The 4L80E is intended to operate between the duty range of the 4L60E and the Allison series transmissions, and prior to the current high-powered light-duty (2500-3500 series) truck diesel revolution, Allison transmissions were essentially only used in the medium-duty class (4000 series) trucks. This made the 4L80E the go-to transmission of the era, amongst the popular Big Block style gas and diesel engines of the 1990’s.

In 2006, with the introduction of the landmark and innovative upstart, the 4L80 began to be replaced in several applications, which was without a doubt GM engineers’ ultimate intention. Yet, the 4L80 continued to be used in the GM’s truck line-up such as in 2007 when it was introduced into the Suburban and Yukon XL vehicles with the 6.0L engine.

The 4L80’s staying power found it installed in several vehicles through 2009, such as the G-series vans, the AM General Hummvee, the W-Series, Isuzu and Workhorse chassis trucks. GM 4L80E transmissions are often overlooked, yet is a top-rated leading option. This four-speed overdrive trans works with just about any power level and engine combination. It is based largely on the TH400 in strength and parts. The difference is the added overdrive gear, advanced electronic controls, and a lock-up torque converter.

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TH400 Transmission Spotlight

th400 th-400 turbo 400

Turbo-Hydramatic or Turbo Hydra-Matic is the registered trade name for a family of automatic transmissions developed and produced by General Motors. These transmissions mate a three-element turbine torque converter to a Simpson planetary gear train, providing three forward speeds plus reverse. The TH400 is highly regarded for its supreme durability. This model has a conservative rate of 450 ft. lbs of input torque, though that can be easily upgraded with aftermarket improvements. These transmissions can come up to a maximum of 1000 torque. The TH400 transmission has available a variety of performance ratings, such as mild, heavy duty, super sport, and SS Xtreme. The higher model that is chosen, the higher rated the horsepower and torque will be.

In its original incarnation as the Turbo-Hydramatic 400, it was first used in the 1964 model year in Cadillacs. The Buick version, which followed shortly thereafter, was known as the Super-Turbine 400. By 1973, THM units had replaced all of GM’s other automatic transmissions including Chevrolet’s Powerglide, Buick Super Turbine 300, and Oldsmobile Jetaway. Starting in the early 1980s, the Turbo-Hydramatic was gradually supplanted by four-speed automatics, some of which continue to use the “Hydramatic” trade name. It is an immensely popular transmission in the automotive industry as well as the aftermarket. Today they are found in GM’s, Jeeps, Jaguars, Rolls-Royces, Ferraris and others.

The THM400 was the first three-speed, Simpson-geared automatic to use overrunning clutches for both first and second gear reaction, a feature that eliminated the need to coordinate the simultaneous release of a band and application of a clutch to make the 2-3 gear change. Owing to this feature, as well as the use of a large, multi-plate clutch to provide second gear reaction, the THM400 is able to withstand very high input torque and an enormous number of shifting cycles, as would be encountered in frequent stop-and-go driving. As a result, it has met with considerable success in commercial vehicle applications.

Gear Ratios of the TH400 are:

  • First Gear – 2.48:1
  • Second Gear – 1.48:1
  • Third Gear – 1.00:1
  • Reverse – 2.07:1

The 400 transmission has a main case of cast aluminum alloy with a length of 24-3/8″ long. Its aluminum case is essentially smooth. The rear mounting face of the transmission has a hex bolt pattern with ribs running forward longitudinally. The fluid pan shape is irregular (see image, left), being likened unto a distorted Texas pattern. The TH400 is the largest of the common GM auto transmissions, but still surprisingly compact in light of the immense power they can handle.

There are two significant variations of the TH400. The TH375 was a version of the transmission used from 1972-1976 in smaller displacement cars. It is identified easiest by its “375-THM” designation cast in the underside of the tail housing. The TH475 was an extra-heavy-duty version, and was found in larger trucks from 1971 on.

By 1980, the relatively heavy THM400 was being phased out of usage in passenger cars in response to demand for improved fuel economy. The THM400 was utilized in the C- and K-series (full-size) Chevrolet/GMC pickups and G-series (full-size) vans until 1990 when GM switched over to the 4L80E. Today, the United States Army HMMWV is the only vehicle using the THM400. The civilian Hummer H1 originally had the 3L80s, but the current model has had a 4L80E since the mid-1990s.

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E4OD Transmission Spotlight


The E4OD transmission system was introduced in 1989 and used in both light and heavy duty applications. The E4OD was the successor to the C6 transmission and was Ford’s first electronically controlled automatic transmission. It comes equipped with four forward speeds as well as electronic shift controls to replace the hydraulic governor control of its predecessor. The E4OD transmission can be found in applications such as the Bronco, the Expedition, and the F-Series:

  • 1990–1996 Ford Bronco
  • 1989–1998 Ford E-Series
  • 1997–1998 Ford Expedition
  • 1989–1998 Ford F-Series
  • 1993–1995 SVT Lightning

Ford’s E4OD automatic transmission was designed from many improvements, changes, and upgrades to the earlier C6 system. Improvements include a higher contact ratio in planetary gear sets, an improved hydraulic pump, and upgraded coast clutch. The E4OD also featured the addition of an overdrive gear set, which greatly improved fuel efficiency over the C6’s direct drive top gear. The E4OD also introduced the concept of electronic shift controls, replacing hydraulic pressure regulation and shift functions with electric shift solenoids. In this transmission, shifts would be commanded electronically by means of the EEC-IV on-board control processor.

Ford called the transmission control processor the ‘Electronic Control Assembly’, or ECA. The unit could also be interpreted as a modern transmission control module, or TCM. The ECA controls transmission shift timing, regulates transmission line pressure, controls the torque converter lockup sequence, and provides certain diagnostics of the transmission. In gasoline applications, the ECA controls electronic functions for both the engine and transmission. In diesel applications, the ECA instead acts as a stand-alone controller for the transmission and does not play a major role in engine function.

The E4OD was eventually replaced by the 4R100, which was Ford’s transition to an alternative name for their drivetrain products, since the transmission is similar to, but not interchangeable with the E4OD. The 4R100 included changes, upgrades, and improvements necessary for Ford’s automatic transmission platform to compete with the F-Series diesel program.

A flashing “OD” light on the shift lever of an E4OD indicates that the ECA has detected a transmission problem and is alerting you to take the vehicle in for diagnostics, service, and/or repair. The E4OD was improved multiple times over the course of its existence – when overhauling the E4OD, so you should consult with your transmission expert to ensure you receive any and all updated components that may provide favorable reliability and durability.

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6R80 Transmission Spotlight


The 6R80 is a six speed automatic transmission made by Ford. It is designed for rear wheel drive vehicles. It was first put into production in 2007 and is still being made today.  It is used in many popular Ford vehicles, including the Expedition, Lincoln Navigator, Explorer, Explorer Sport, Mercury Mountaineer, F150, Ford Territory, Mustang and Ranger. The 6R80 transmission will bolt directly to all Modular and Coyote Ford engines and can be adapted to virtually any vehicle combination relatively easily. With a variety of parts available to simplify the transmission swap, it is an excellent choice for a performance upgrade or when swapping from a manual to automatic transmission.

The 6R80 was first introduced in 2009 and is manufactured under ZF license at the Ford Transmission Plant in Livonia, Michigan. It can be found behind a multitude of Ford engines ranging from the 3.7 V6, all the way up to the robust 6.2L V8. While the transmission is offered in several engine applications, each transmission variation is integrated differently depending on engine and vehicle application. Enhancements were added by Ford to further improve the transmission, including the addition of a ratchet-style low one-way clutch, and removal of the internal TCU for the 2011 model year, easily enabling stand-alone control.

This six-speed transmission features an elegant, robust, band-free design that is simpler than most four speed automatic transmissions. It uses five clutch packs and a single one-way clutch to achieve six forward ratios, whereas most four speed units utilize six or more clutches and/or bands, with at least one one-way clutch to achieve four gears. This allows better reliability, better shift quality, and reduced rotating mass.

Although the 6R80 has 6 forward gears, the transmission is only slightly larger than earlier four-speed automatics. The transmission is without question stronger than earlier Ford 4 speed transmissions. The 6R80 can likely handle up to 1000HP with proper ECU tuning and potentially even more with the implementation of aftermarket components. Stock applications already employ a multi-plate torque converter clutch, enabling greater power handling in lockup. Despite having 6 forward gears, the transmission is only slightly larger and heavier than light-duty four-speed automatics, such as the 4L60E and 4R70W.

One primary advantage of using a six-speed clutch-to-clutch transmission, like the 6R80, is the tighter gear ratios when compared to traditional four speed automatics. From first to sixth gear, there is a 604:1 ratio spread. This efficiency will not only improve the acceleration and performance of high-horsepower applications, but also make a dramatic improvement when applied to near-stock or mildly-modified vehicles. With six gears, it can better utilize each ratio to get the most efficiency and performance out of your vehicle’s combination.

The gear ratios offer a generous ratio spread of 6.04:1 from first to sixth gear, and the ratios are very close together, rivaling most four-speed transmissions. From second to sixth gear, the ratios are extremely close, providing world-class performance. The 6R80 also uses synthetic transmission fluid (Mercon LV). The transmission used in the Ford F-150, has a fluid capacity of 12.10 quarts and weighs roughly 215 lbs. The 6R80 measures 23.75” and utilizes a large 31 spline 4wd output shaft. In 2011 Ford removed the internal TCU enabling the usability of stand-alone computers.

Sooner or later you will be faced with a decision to replace the 6R80 transmission in their vehicle, be it from excessive mileage or from overheating the transmission. We highly recommend that you consider buying a remanufactured transmission over one that was simply rebuilt. Ideally, you should keep the transmission below a maximum temperature of 200 degrees. For every 20 degrees you go over 200 degrees, you cut the potential lifespan of the transmission by a factor of two.

This transmission has been largely avoided or ignored in the past due to a stand alone control system not being available. There is already a growing ecosystem of swap parts available for the 6R80, including bell housing adapters for various non-modular Ford V8s, with others likely to follow. The best way to combat excessive heat is to install an aftermarket transmission cooler on your customer’s vehicle before it ever overheats, so for a little added protection, consider installing a transmission cooler with a built in fan.

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48RE Transmission Spotlight


The 48RE four-speed automatic transmission represents an evolution of the previous 47RE transmission model and can be found combined with the Cummins Turbodiesel in Ram pickups from 2003 to 2007 model years. The 48RE transmission design is both heavier and stronger than the 47RE, although the two transmissions share identical ratios. Although the 48RE is considered a significant improvement over its predecessor, it quickly became outdated as power ratings for the Cummins Turbodiesel surged to over 600lb-ft by 2007, the last model year of the 5.9L Cummins ISB. Chrysler would ultimately replace the 48RE transmission with its first diesel specific transmission platform, the 68RFE, following the development of the 6.7L Cummins.

The 48RE transmission features four shift schedules, technically known as governor pressure curves. Governor pressure is electronically controlled relative to engine speed and is used to command upshifts and downshifts according to engine speed and load. The four schedules are as follows:

  • When transmission fluid temperature is at or below 30° F – Shifts are delayed and the engine is allowed to rev higher to help the engine and transmission reach normal operating temperature in less time. Shifts are typically harsh while this schedule is in effect.
  • When transmission fluid temperature is at or above 50° F – The transmission’s normal adaptive shift strategy is in effect. The adaptive strategy is a dynamic shift schedule that commands upshifts and downshifts based on various operating conditions, including engine speed and load.
  • With “wide open throttle” – At full throttle, upshifts are originally commanded by the PCM at predetermined optimal engine speeds. The PCM perpetually learns and creates an optimal upshift schedule based on the time required to complete a shift at a given engine speed/load compared to the desired preprogrammed values. The wide open throttle shift schedule is therefore adjusted routinely based on the outcome of transmission shift events.
  • When transfer case 4WD low engaged – In order to compensate for inherent accelerator pedal sensitivity in low range (resulting from significantly higher engine torque multiplication through the drivetrain), the PCM will command upshifts much sooner when the transfer case is placed in the lower range.

The transmission also features a “Tow/Haul” setting that can be activated by a shifter-mounted switch. The 48RE’s Tow/Haul function is not necessarily a “smart” function like those found on modern engine/transmission combinations that have integrated exhaust brake technology and vehicle speed management systems. When the Tow/Haul setting on the 48RE is activated, torque converter lockup is engaged and the transmission shift schedule eliminates overdrive (4th gear) upshifts, therefore direct drive (3rd gear) becomes the final available drive gear. Towing significant weight in overdrive is not recommended, as drive wheel torque is reduced and the load placed on the transmission can contribute to a reduced product lifespan.

The 48RE automatic transmission features an actual input torque rating between 560 and 570 lb-ft of torque; whereas, the standard Cummins Turbodiesel peaked at 610 lb-ft by 2005. As a result, the 5.9L Cummins was designed to detune itself when necessary to promote the longevity of the transmission. The engine will produce its peak 610 lb-ft torque, but only in cases where accessory load brings the actual engine torque output into the 570 lb-ft torque range. In all other cases, the engine will detune to roughly 570 lb-ft of torque under full load. The limits of the transmission are quickly realized in the presence of performance enhancing modifications such as electronic tuning devices.

The 48RE transmission is the weakest point on a Dodge Cummins truck. Not only do they fail on trucks with minor upgrades, but even stock vehicles have been known to be too powerful for the transmission to endure its natural lifespan. A heavy duty truck needs parts which can stand up to heavy trailers, stop-and-go commutes to work, or high-horsepower applications. That’s why we might recommend modifying the transmission to make it the strongest and most reliable part of your drivetrain.

Modern diesel performance is still advancing at a radical pace. Current pickup truck engines can make nearly 1,800lb-ft of torque at the wheels yet still be driveable on the street. Getting that much power to the ground; however, is another matter altogether, and virtually every single part in a transmission could be its weak weak link. Make sure you have the right components in your truck, whether you currently have a 48RE automatic transmission or are looking to replace your current system with one of ours.

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5R110W Transmission Spotlight


The Ford 5R110W transmission is a heavy-duty five-speed automatic transmission. It is primarily used in the Ford F-Series Heavy Duty pickup trucks and their Heavy Duty Chassis program. The 5R110W is loosely described as a redesign of Ford’s earlier 4R100 automatic transmission. The 5R110W “TorqShift” transmission was introduced alongside the 6.0L Power Stroke diesel for the 2003 model year as a diesel specific transmission which is closely integrated into the function of the engine. This transmission is good for towing, snow plowing, 4WD, or for any other similar high-performance needs. Many of these can be found in delivery trucks, food trucks, school buses, and motorhomes.

The transmission is advertised as a five-speed, although in actuality it features six forward speeds. Under normal operating conditions, the transmission shifts 1st-2nd-3rd-5th-6th. A secondary shift sequence is commanded when the ambient temperature drops below 5° F and shifts 1st-2nd-3rd-4th-6th. The transmissions marginally shorter 4th gear is used in cold weather to force higher engine speeds and therefore help the engine/transmission reach the normal operating temperature in less time.

Since they are often used in vehicles that are used and abused in harsh environments, the 5R110W transmission is often given a rough ride, with the number one killer of the 5R110W being excessive heat resulting from abuse. Towing over the factory payload limit and keeping your foot on the gas going up steep hills with a heavy load are two of the most common examples of this type of abuse. So here’s the bottom line: if you have a programmer, power adders or tow heavy loads, then you must have a High Performance or Heavy Duty transmission and torque converter so that your transmission will last.

The 5R110W is unique in that it lacks a typical valve body – instead, the 5R110W contains a “solenoid body”, which contains a series of 7 electronic shift solenoids. Problems with the 5R110W can be vaguely separated into two main categories. Mechanical problems may include a physically stuck solenoid, worn clutches, damaged gear set, while electrical problems may include a solenoid that is not functioning correctly, faulty or missing input from one of the various sensors, etc. Engine problems may be inappropriately diagnosed as a transmission issue and therefore should be repaired before attempting to troubleshoot a transmission.

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68RFE Transmission Spotlight

68RFE Transmission, Level 3 - Extreme Duty RAM 68. 68RFE Full Billet Everything Transmission and Torque Converter

Chrysler’s 45RFE transmission, launched in 1998, used three planetary gear sets instead of the normal two being used at the time. The transmission later evolved into Chrysler’s first diesel specific transmission, the 68RFE, which was introduced alongside the 6.7L Cummins turbodiesel during the 2007 model year with the Ram and Pickup Lines. The newer transmission design provided the benefits of modified internal components to handle the increased torque and revised gear ratios for larger applications. Monster provides a wide variety of different builds for this transmission for additional ratings of horsepower and torque. These include the Heavy Duty, Super Duty, and Super Duty Xtreme models of Dodge Ram trucks.

The transmission’s band-less design and upgraded filtration system have proved to be significant improvements over previous transmissions, allowing for extended time between service intervals, while also reducing service costs. Under partial throttle, shifting into gears above third was delayed; and the system was likely to kick down under part throttle into fourth and fifth. A new Tow or “Haul” mode allowed for faster and crisper shifting in order to reduce engine wear, while still allowing overdrive unless the driver has previously locked it out. The 68RFE transmission was the biggest leap forward in terms of Dodge automatic transmissions since the inception of the Dodge Cummins power plant.

In the past, four-speed transmissions were the weak link for the vehicle’s powertrain. And while the 68RFE has proven itself in many respects, it has also shown plenty of weaknesses, as well. As power is increased above stock, heavy loads are hauled, and miles are racked up, the 68RFE’s are failing, partly due to the electronically controlled nature of these transmissions.  The 66RFE was introduced in 2012 as a lighter-duty version of the 68RFE, with the main differences between the transmissions being in the torque converter.

The 68RFE kept the basic clutch and hydraulic control design, matched with heavier-duty planetary gears, toothed differently to increase their capacity. The shafts, clutches, pump, torque converter, and other parts were also redesigned to handle the Cummins 6.7 liter diesel. The 263-pound 68RFE has roughly the same torque capacity as the Aisin automatic option in Ram heavy-duty pickups, but the Aisin allows for a power takeoff (or PTO), while the 68RFE does not; the Aisin also had a steeper first gear for better off the line power, with the same sixth gear ratio.

The processes involved to build more robust replacement parts has been tedious for the aftermarket manufacturers.  However, with several years, and many miles under their belts, most of the manufacturers have determined the best methods to manufacture “bulletproof” replacement parts, leaving a wide selection of proven parts now available.

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Allison 1000 Transmission Spotlight

Allison 1000

The Allison 1000 is a 6-speed double overdrive transmission produced by the Allison Transmission Company in Indianapolis, IN, and Baltimore, MD. Allison transmissions have a global reputation for being extremely durable, which is why they’re cheaper to operate than other equally equipped vehicles. The low minimum maintenance requirements result in cheaper overall maintenance costs.

This heavy duty transmission can be found in all sorts of motorhomes and custom applications, along with the Chevrolet Silverado, the Hummer H1, the Chevrolet B-Series and the GMC Sierra. It can also be found in the Chevrolet Kodiak and the GMC Topkick. Starting in 2001, Chevy 2500 HD and 3500 trucks have had the option of being equipped with the Allison transmission. The Duramax-powered engine in the Silverado 2500 and 3500 trucks are now combined with the Allison 1000.

The Allison 1000 is an extremely heavy duty transmission, capable of handling up to 620 lb-ft of torque. Compare this to GM’s highest-rated transmission, the 4L80E which can only handle 420 lb-ft of torque. Put into use in 2006, the Allison 1000 transmission is still in production.

Early Allison 1000’s were initially 5-speed transmissions, but in 2006 they added a sixth overdrive gear. The creators of the Allison transmission realized that the diesel engines offered in diesel pickups were constantly increasing in horsepower and torque. The creators of the Allison transmission realized that the diesel engines offered in diesel pickups were constantly increasing in horsepower and torque. They knew that a strong transmission would be needed to handle GMC’s Duramax engine.

The adaptive learning technology provides a comfortable driving experience and helps you avoid any rough shifting experiences. The Allison 1000 is completely electronically controlled to adapt to your current driving style. The computer in the Allison 1000 constantly adjusts shift clutch pressure to match engine torque and vehicle load. The computer also has pre-programmed tables for reference. It attempts to make the shifts match the programmed table to maximize durability and drivability.

Most commonly, the transmission may go into “Limp Mode” during the 4 to 5 upshift or between 5 to 4 downshift while under hard acceleration. This will cause a check engine light to come up on your dash and the truck to be limited by power and speed. When this happens, the most common reported code is P0700. GM defines P0700 as “Transmission Control Module Requested MIL Illumination”. Simply put, it’s a general code for transmission issues and generally is accompanied by another code such as P0701, P0702 or others.  

Many truck owners’ first reaction is to replace the Transmission Control Module (TCM) as soon as this code pops up. The reality is that further diagnosis is needed to tell what the issue is for sure, and the best way to resolve it. Never jump to conclusions with your transmission, and always take into consideration the circumstances behind the issue prior to the code coming up if you experience any problems.

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4L60E Transmission Spotlight

4L60E / 4L65E / 4L70E Transmission, Level 5 "4L60E Extreme Raptor" (4L75E +)

The 4L60E is a four-speed automatic transmission produced by General Motors. It has been considered to be the best rendition of the finest overdrive automatic transmission ever produced. General Motors first induced the 4L60E transmission in 1993 as a replacement/upgrade to the 4L60, which itself was an upgrade from the 700R4. The 4L60E is a very capable 4-speed transmission with a 3.059 first gear ratio and a 0.696 final gear ratio, making it ideal for off the line performance while still providing decent mileage in overdrive.

The Corvette is General Motors flagship car. The 5th generation Corvette was a huge leap for GM. It incorporated so many new state of the art components over its predecessor that there are too many to count. The 4L60E differs from the 700R4 by being fully electronically shifted, and it has many internal upgrades that make it both stronger and more durable. The 4L60E could be found in many General Motors vehicles, including the Chevy Camaro, the Pontiac Trans Am, the Chevy Silverado, the Cadillac Escalade and the Buick Roadmaster. It is probably best known for its use in the 1994 -2004 5th generation Corvette.

While it’s common for car owners to perform many engine modifications, few give much thought to doing anything with the automatic transmission. Did you know you can pick up a full second, or more time reduction in the quarter mile by modifying your 4L60E transmission in your Corvette? Yes, it’s true and it’s not difficult to do. Let’s take a look at a few modifications you can make to the transmission in your GM or Chevy vehicle!

Shift Kits – There are a number of different shift kits available from a variety of different companies. Most of them come with the option to set them up for towing, street or street/strip use. Street/strip mode will usually result in the chirping of the tire under full throttle in first gear, given the ideal rear end gear ratio and adequate power levels. Shift kits can be broken down into two categories: modified valve bodies and electronic shift kits. Modify valve bodies use special plates with different size holes and check ball, stiffer springs and plugs to change the shifter characteristics.

Torque Converters – The stock converter used in the 4L60E is of the lockup type. Because of this, it is recommended that a stall converter of no more than 2600 rpm’s be used. A non-lockup converter is also available for those that want a higher stall speed. A popular option on the higher horsepower applications is the use of a converter with the anti-balloon plate option.

Transmission Coolers – There are literally hundreds of different types of transmission coolers available. It is always recommended to use the largest cooler possible. Coolers are available in the standard tube-type configuration and a more rugged stacked-plate design. Coolers are also available with built-in fans and temperature switches.

Transmission Pans – Most aftermarket pans are designed to increase the fluid capacity of the transmission. They are available in steel, chrome plated steel, and aluminum. Some have cooling fins or cooling tubes built into them. Most of them include a drain plug. Aluminum pans are generally sturdier and dissipate heat better than steel pans.

Wire Harnesses –  If the car originally came with the 4L60E than use of the stock wire harness is fine. For retrofit applications, special customer wire harnesses are available to work with either the factory computer or an aftermarket controller.

Fluids –  You can use the organic oil called for in the GM manual or you can use a synthetic fluid that meets the minimum requirements. Be sure to check the requirements for your individual year transmission and don’t forget to change the fluid on a regular basis. There are many options to upgrade the 4L60E to meet your requirements and desires.

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700R4 Transmission Spotlight

Automatic Transmissions - 700R4 Transmission Type - Upgraded torque converter, servo, sprag and pressure valve

General Motors/HydraMatic introduced the 700R4 4-speed automatic transmission in 1982 (as a replacement to the TH350 3-speed automatic transmission) and used it in many of their popular vehicles with models beginning in the years through today. The 700R4 was one of the first overdrive transmissions used in General Motors vehicles from the Blazer to pickup trucks, and even the Corvette platform. The transmission is sometimes also referred by as the 4L60 (1990) or 4L60E (1993) for improved electronically-controlled models introduced later on. The 700R4 overdrive transmission platform is considered one of the best ever made.

The 700R4 automatic transmission is constructed of a single piece of cast aluminum. The part is 23.4 inches long, weighs 155 pounds, and holds approximately 11 quarts of transmission fluid. It is distinguished from the TH350 and TH400 in that it has a square oil pan, lacking the distinctive cut-off corner of the TH350 and the “Texas” shaped oil pan under the TH400. The transmission was primarily developed to improve fuel economy, which was achieved by the 30% overdrive capability, as well as the improved 3.06:1 gear ratio in 1st gear.

The first 700R4 had an input shaft with 27 splines, though this transmission design was prone to failure because it was unable to handle the load properly. In 1984, they introduced a 30 spline input shaft that was much stronger and reliable. The transmission typically has 1/4” pipe fittings on the passenger side for an improved cooling circuit. Later versions also use a pinned flare and o-ring design for the fluid cooling circuits. The 1987 and newer produced transmissions are considered to be refined and very reliable when performance is compared in 350 V8s in sports cars and trucks.

The physical swaps in the 700R4 transmission are straightforward to install, but the one component that confuses many owners and mechanics is the throttle-valve (T.V.) cable setup. If the T.V. cable is not set correctly, the transmission will underperform and cause its lifetime to be greatly shortened. Each time you adjust this component, you will need to reset the cable slider correctly while using the pressure gauge. This will ensure instantaneous pressure response with the new setup – this is critically important! If you operate the transmission with low hydraulic pressures, it can cause a transmission failure very quickly.

The front-facing TH700 unit is natively compatible with either the Chevrolet 90-degree “Small Block” & “Big Block”-patterned engines, including the V6, V8, I6 & Iron Duke I4 varieties. The General Motors 60-degree pattern engine can be mated to 60-degree style engines like those in the 3800, 3.4, and other engine families. These other transmission types are fairly rare since they were only produced for a few years for the Chevy S10 and Camaro with the 2.8L V6, prior to GM’s upgrade to the 4.3L V6 engine.

We offer 700R4 Transmissions with Torque Converter – Level 1, Level 2, Level 3, Level 4, & Level 5 as well as 700R4 Transmissions with Torque Converter – Level 2 for 4×4 vehicles on our website. Call us today or order directly through our website!

The transmission has the following dimensions and gear ratios:

Case to External HousingOverall LengthBell Housing to Mount
23 3/8″30 3/4″22 3/8″


Transmission1st Gear2nd Gear3rd Gear4th Gear Overdrive
Turbo 3502.521.521N/A
Turbo 4002.481.481N/A
700R4 /4L603.061.6310.7

General Motors Vehicle Models Using the 700R4 or 4L60E Transmissions:

1982-1992 Chevrolet Blazer/GMC Jimmy

1982-2005 Chevrolet Corvette

1983-1996 Chevrolet Impala and Caprice police specials equipped with 350 engines.

1983-1985 Oldsmobile 350 Diesel equipped models.

1983-2002 Chevrolet Camaro/Pontiac Firebird

1985-2005 Chevrolet Astro/GMC Safari

1991-1992 GMC Syclone

1991-1992 Oldsmobile Custom Cruiser

1989-2003 Chevrolet S-10/GMC S-15/Sonoma

1989-2005 Chevrolet S-10 Blazer

1989-2001 GMC S-15 Jimmy

1990-1996 RWD Cadillac Fleetwood/Cadillac Brougham/Cadillac Limo

2002-2009 Chevrolet TrailBlazer/GMC Envoy

1992-1993 GMC Typhoon

1984-2010 Chevrolet Suburban

1982-2012 Chevrolet Van

1994-1996 Chevrolet Impala

1994-1996 Buick Roadmaster

1982-2010 Chevrolet C/K

1993-2010 Chevrolet Tahoe/GMC Yukon

1999-2006 Cadillac Escalade

2002-2008 Chevrolet Avalanche

2003-2007 Hummer H2

2004-2007 Buick Rainier

2004-2012 Chevrolet Colorado/GMC Canyon

1988-2006 Holden Commodore

2004-2006 Pontiac GTO

2005-2009 Saab 9-7X