The A8TR1 and A8LR1 Hyundai/Kia's 8-Speed Rear-Wheel Drive Units Come of Age!
The automotive engineering world took notice when ZF came out with the first rear-wheel drive 8-speed transmission in 2008. Soon afterward, other manufacturers followed suit. Then, in 2012, Powertech, Hyundai’s powertrain division, produced the A8TR1 transmission. It debuted behind the Hyundai Genesis V8, followed by the Equus and Genesis coupe. They also introduced a lower […]

The D7GF1 and D7UF1 - A Closer Look at Hyundai/Kia DCTs
Dual-clutch transmissions have become more prevalent in a quest to improve car fuel efficiency. The absence of a torque converter and an engine-driven oil pump significantly reduces horsepower consumption. Also, adding a direct mechanical transfer of torque through gears produces the most efficient throughput of any transmission. Because of these attributes, they have found a […]

The Toyota AC60E: Simpler Can Be Better!
Since the days of the A40 and A340 units, I had engraved this image of Toyota rear-wheel drive transmissions in my mind. From the long, rectangular oil pan with a valve body to match it to the sharp clutch splines in the case that always left me cut up, not much has changed with them […]

Six-Speed Success! 62TE Things To Do To Deliver Them Right The First Time
The 62TE transmission is Mopar’s answer to increasing the fuel efficiency of their front-wheel drive vehicles. While it is fundamentally a 41TE with an underdrive assembly on the countershaft, it has its own personality as well as problems. Pattern failures have emerged with these units over the 15 years they have been in the industry. […]

Spotting Imitation Filtration! Checking Filters for Flaws
Let’s face it. They don’t make people like they used to! It seems like all aspects of life have been touched by this simple truth. Therefore, we can’t expect parts to be made as they used to. Just because a part is new doesn’t mean it will work as designed. We must take the word […]

It's a Balancing Act - A Look at Balance Oil and Shift Quality Issues
Electronic components inside today’s transmissions have captivated us when considering parts to service and replace on a rebuild. Since computer strategy plays such an intrusive role in the operation of most units, the sensors and actuators inside the unit come into question, especially when there are shift quality-related issues that aren’t supported by damage or […]

Worth Another Look! Subaru Lineartronic Failures, Faults, And Fixes!
Since the introduction of the Subaru Lineartronic in 2010, there has been an air of mystery surrounding this newly designed CVT unit. Anyone who has witnessed the antics of the Subaru Justy CVT no doubt was scratching their head with wonder and amazement at the gall of the Subaru engineering department to even suggest putting […]

Things That Go Bump - 6T70 Transmission Shift Quality Issues
Building late model transmissions seems to be easier than building some of the earlier model 4 speed units, at least mechanically. Once you learn the do’s and don’ts for a particular unit, it is as easy as walking in the park on a Sunday afternoon! That is how most of us are with the 6T70 […]

They're Here! The 8L90 Transmission Reaches The Aftermarket... With Problems!
There was an iconic scene in the 1980’s horror movie called Poltergeist where a child is in front of a television screen that was left on but not tuned to a channel. After a while, she announced to her family, ‘they’re here!’ In this case, she was referring to the arrival of the undead spirits. […]

FCA's M40MTA Transmission - A Manual Transmission With a Helper!
A manual transmission is one of the most efficient ways to get power to the ground from an engine. With the simplicity of selectable gear reduction and the ability to control power to the transmission through a clutch system, a driver has ultimate control over how to deliver the engine’s power to the ground. Also, […]

Mistaken Identity! Shudder Sensation in GM Rear Wheel Drive Issue After Rebuild
Today’s drivetrains are more efficient than ever before. Every component is designed to maximize the transfer of power with the minimum amount of waste while maximizing the driver’s comfort and overall experience. Powertrain management computers control the engine, transmission, and related systems to prevent wasting fuel. With a micromanagement level of control in play comes […]

Transmission Strategies That Save Fuel! Start/Stop and Neutral-Idle Powertrain Management
Automobile manufacturers are exploring every way possible to make vehicles more fuel-efficient. Powertrain management strategies are tailored with this in mind, while simultaneously maintaining a seamless and responsive driving experience. The result is a combustion engine coupled to a transmission with systems added to control and maximize the efficiency of every drop of fuel that […]

Putting the Rubber to the Road! Ford's Light-Duty All-Wheel Drive System
Small sports utility vehicles and cars with all-wheel drive capability are becoming more commonplace. Every major auto manufacturer has its version. High-speed CAN bus networks, powerful computers, and lightweight drive components make adding all-wheel drive to existing front-wheel-drive models in their lineup more practical. Besides providing added traction and control on adverse road conditions,...

Challenging Times - A Dodge Challenger with an 845RE in Failsafe
A customer came into the shop with a 2016 Dodge Challenger with a 3.6L motor and an 845RE transmission with a no-shifting complaint. He owned the vehicle from new and experienced a no-start condition one morning. Being a do-it-yourself kind of person, he jump-started his car a few times and eventually replaced the battery. After […]

Engaging Moments! Ford's Vacuum-Actuated Locking Hub System, Diagnosis and Issues
Convenience and ease of operation are things we have come to expect out of our daily driving experiences. Pushing a button should give us exactly what we want immediately. This is what we have grown to expect from our 4-wheel drive systems. Since the introduction of shift-on-the-fly 4-wheel drive, automakers have taken a multi-step process […]

The Devil's in the Details! A Machinist's Look at the 6L80/6L90 Units
The 6L80 and 6L90 transmissions have become the most popular rear-wheel drive GM transmissions in most of our shops. We have seen several patterned failures, written numerous articles, and found countless fixes to keep these units on the road (and the list doesn’t end). With so many of them in need of repair, they have […]

The ZF 8HP: It's Shift Strategy, No Problems Here! Adaptive Strategies and How They Affect Your Diagnostic Process
The ZF 8-Speed transmission is a well-balanced unit that seamlessly fits into powertrain management systems. With a blend of shift quality, gear ratios, unit footprint, efficiency, and durability in one package, it produces stellar performance under every conceivable situation. However, the mechanical and hydraulic engineering only works so well due to the electronic powertrain management [&hellip...

Get in Line! A Machinist's Look at the 6L80/6L90 Pump Alignment
The 6L80 and 6L90 transmissions have been in the aftermarket for over a decade. By now, most transmission shops see these transmissions regularly. One common issue that brings these units to your shop is torque converter failure, which also destroys the pump. With this in mind, many shops are prepared to replace or repair the […]

Introducing the Toyota AC60E
Toyota’s 6-Speed Saga Continues… With Fewer Parts! Since front-wheel-drive vehicles are a better choice for fuel efficiency, rear-wheel-drive vehicles are becoming less popular. With the added weight of a differential assembly, driveshaft, and support components, there is really no way for a rear-wheel-drive vehicle to win the pole position in fuel economy. However, in truck […]

The ZF 8HP: The New Kid on the Aftermarket Block!
When I was a kid growing up in a small, east coast city, there were other kids who moved in and out of our neighborhood regularly. Then there was that one kid that arrived and we knew he wasn’t going anywhere anytime soon. He was the kid that seemed to fit in without any problems, […]