Keith Clark - January/February - 2021

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 become a common unit to build. Unfortunately, with common units can come rout...
Keith Clark - December - 2020

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 strategy...
Keith Clark - December - 2020

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 pump assembly as necessary. Since these units are so popular now, many s...
Keith Clark - October/November - 2020

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 and performance spo...
Keith Clark - September - 2020

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, and he was easy to get along with. This is the role that the ZF 8HP transmission has found in the transmission indus...
Keith Clark - July - 2020

Since Chrysler introduced the A604 transmission in 1989, controlling the power feed to the transmission was a major concern. Low resistance, fast acting pulse width modulated solenoid circuits needed to be monitored and tested constantly to ensure the computer would not be damaged. When shorts to power, shorts to ground and open circuit faults are detected, the PCM is programmed to immediately cut...
Keith Clark - May - 2020

Toyota has always maintained a unique approach for managing shift quality. Ports lined up in a case like missile silos loaded with accumulator pistons and specifically calibrated springs were their trademark weapon for ensuring good shifts. Since the introduction of pulse width modulated solenoids, shift quality management duties have slowly drifted away from accumulators and orifices in hydraulic...
Keith Clark - April - 2020

Adaptive shift quality technology has been with us since the late 1980’s. Chrysler’s A604 is the most noteworthy trailblazer of this technology. Since then, every manufacturer has followed with their own version of shift quality adaptation. With increased computer processing capacities came more advanced methods for managing shift quality. Of course, with increased complexity comes opportunity...
Keith Clark - January/February - 2020

Commercial airliners don’t leave the ground without a pilot and a co-pilot at the controls. They work together as a check-and-balance to ensure that everything from preflight to post-flight goes successfully. This is an added safety measure to minimize the probability of human error related accidents. Driver assistance devises have been introduced into the automotive industry for the same reason...
Keith Clark - December - 2019

The U660E first appeared in the Lexus ES350 and the Toyota Camry in 2007. Then it showed up in the 2008 Avalon, followed by the Venza in 2009. It is used behind the V-6 engines. The U760E was first used in model year 2010 for 4-cylinder application motors. These units have logged thousands of miles and have become more common in repair shops. As these units age, they are showing common issues. Her...
Keith Clark - October/November - 2019

Recently, I was in Australia for a seminar presentation. During my time there, one of the shops told me about an intermittent problem they had with a 2012 Toyota Prado 150 series with a 3.0L diesel engine and an A750F 5-speed transmission.
For us here in the US, this vehicle would be akin to the Toyota 4runner. The complaint was that the transmission would drop out of 5th gear intermittently. I...
Keith Clark - September - 2019

We are bombarded by new transmissions everywhere we turn. Manufacturers are doing everything they can to gain an advantage in fuel economy and driving experience satisfaction. The transmission plays a vital role in both of these areas. That’s why there is such a variety of transmission types on the market today.
Direct Shift Gearboxes (DSG’s) are becoming a very popular choice to provide th...
Keith Clark - July - 2019

A look at an uncommon problem with a common unit
The RE5R05A made its debut in 2002 in the Infiniti Q45. Since then, it’s become standard equipment, an automatic rear wheel drive transmission found in most models for Nissan and Infiniti. Variants of this unit are found in some Kia and Subaru applications as well. Nissan used this unit up to model year 2015 in the Armada. Now, at 17 years old an...
Keith Clark - June - 2019

Technology continues to change the nature of automatic transmissions. With Continuously Variable Transmissions (CVTs) and Direct Shift Gearboxes (DSGs), planetary-based automatic transmission technology had to make advances in order to maintain relevance. Tipping the scale in technological genius is the 8L90 transmission. Utilizing a stand-alone TCM, a clutch-to-clutch gear train control set up an...
Keith Clark - May - 2019

The most successful managers and technicians in the automotive industry are fully aware of the need for continued training, to prevent being blindsided by advances that others have experienced and are willing to share. This is what Vision EXPO is all about. It’s a gathering of the brightest minds in the industry with a common goal: to expand their horizons through classes and interaction with ot...
Keith Clark - April - 2019

Leave it to Honda to create a transmission that the world has never seen before. Ever since the H2 Hondamatic transmission was introduced in 1973, Honda transmissions have been dubbed as strange, different, or unique, depending on one’s point of view. Transmission builders worldwide either love them or hate them.
Holding true to this history, in 2015, Honda introduced an 8-speed, direct shift...
Keith Clark - March - 2019

Starting with model year 2005 with the 6F50N family transmissions, Ford introduced solenoid strategies. Since then, they’ve introduced the 6F35N, 6R80 family, and the 6R140 units with solenoid programming needs.
It can be a strange and ominous item to deal with from diagnosis to the final test drive. Any test drive with poor shift quality might have you wondering whether the computer needed t...
Keith Clark - January/February - 2019

The DPS6 transmission in Ford Fiesta and Focus models has been around long enough for us to accept that they aren’t going away. In fact, this type of transmission is preferred for high-end, high-performance vehicles.
For argument’s sake, consider this an entry-level unit. It’s a direct-shift gearbox (DSG) consisting of a dual, dry-disc clutch assembly, fully controlled by an external tran...
Keith Clark - October/November - 2018

Building the A5HF1 and A5MF1 units have become almost second nature to builders in larger, metropolitan areas. These units are more predictable than their parent unit, the KM. But they can become annoying and overbearing if you don’t pay attention to details that could mean the difference between a job that stays gone versus one that has many unhappy returns.
Let’s look at the A5HF1 in a 20...
Keith Clark - August - 2018

Exploring the purpose for the Service Fast Learn Adapts procedure.
By now, most builders in major metropolitan areas have developed a process for building the 6T40 successfully. They’ve tailored their parts order to the failure observed inside the unit. When they need to replace the TECHM, they know to arrange for programming to maintain a reasonable delivery date.
With everything happening ...