Cars, Culture, and the Modern World

Sophia Relph is a mechanical engineer who researches fluid mechanics by day, and writes about cars by night. This blog intends to not only explore the physical and mechanical nature of automobiles, but to investigate their cultural significance and the meaning they impart as texts and works of art.

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Manumatic Transmissions: A Technical History

Word count: 2987 (~17 minutes), Last modified: Tue, 18 Feb 2020 19:41:51 GMT

Stick shifts on the way out?

Perhaps sadly, it is getting more and more difficult to find new cars with manual transmissions in the United States. The new eighth-generation Corvette will not feature a manual gearbox, and the last GM economy car to feature a manual transmision seems to have been the 2019 (pre-refresh) Chevrolet Sonic. Many budget-oriented subcompacts (Yaris, Versa, Accent) do offer manual transmissions, but sportier models seem to be increasingly focusing on dual clutch transmissions or straight up automatics. Car enthusiats of course mourn the disappearance of manual transmissions, and for good reason: a manual transmission offers intuitive and direct control of drivetrain behavior, virtues which enthusiasts naturally prefer. That said, however, the landscape is changing: modern automatic transmissions offer more gear ratios and gear selection algorithms that outdo even the most dedicated 1990s hypermiler, and typically feature better fuel economy than manual transmissions, defeating the traditional logic that manuals get better fuel economy. Even on the performance front, modern automatics like the ZF 8HP shift far quicker than manuals, and even approach the shift speeds of dual clutch transmissions (though DCTs will probably always reign supreme on shift speed). More and more performance cars are using torque converter and planetary gearset automatic transmissions, and it seems that the dominance of those gearboxes is cemented.

But fear not! Most modern automatics come with a manual shifting mode, otherwise called manumatic, or Tiptronic, or Geartronic, or Tap Up/Down Shifting, or any number of other trade names. All of these manumatic modes, implemented by various manufacturers, involve approximately the same user experience: Move the shifter into a "Manual" detent (or Sport mode, or simply hit a paddle shifter), and then the transmission delegates (most) shift control to the driver. This allows the driver to delay or advance shifts, or hold gears, giving her a deeper, more involved interaction with the vehicle, all while not having to worry about working the clutch or bungling shifts. Manumatic systems are of course not without their limitations-because they are electronic facilities and not fully mechanical, the transmission control unit still holds the final word on shift control, and it can prevent shifts that might stall or overspeed the engine, and also offers quality-of-life features like automatically shifting to first at a stop, preventing the driver from having to cycle down through every gear sequentially. Of course, the TCU also controls shift speed and torque converter clutch lockup, both of which affect the feel and dynamical behavior of the transmission. Thusly, manumatic modes really only provide a fraction of the controllability of fully manual transmissions. This is of course a major sticking point for many enthusiasts and purists-it's not uncommon to hear people say "if it hasn't got a clutch, it's not a manual" or "if you like shifting for yourself, just get a stickshift car." These are valid points: No, a manumatic-capable transmission is not a manual, and yes, a manual gearbox offers a level of interaction orders of magnitude greater. But those who rail on about the pointlessness of manumatic modes may well miss the point: manumatic transmission operation is not a replacement for a manual transmission, but rather, is an advance in automatic transmission development. This should not be seen as a huge leap forward in transmission design and UX/UI design. Instead, we should consider the technological context and history of automatic transmission operation: Doing so, we realize that manumatic modes are an incremental improvement, a single evolutionary step forward, not a whole new animal.

Where did it all start?

We of course know that car manufacturers have been trying to make manual shifting easier and less complicated for ages; attempts at this include the plethora of different clutchless manual transmissions that automakers have attempted over the years-some used a torque converter, others used an electronically controlled clutch, but the intended use case remained the same: Gear selection without the clutch pedal. In some ways, the manumatic transmission control is the ultimate development of these, leveraging the very reliable mechanisms of modern torque converter automatics with electroncic control. However, car manufacturers have also been trying to improve the behavior of their torque converter automatics for a very long time. This is where we should seek the technological origins of manumatic operation.

The most fundamental requirement for manumatic operation of a transmission is electronic control. This enables the inclusion of the self-protection logic that makes manumatic modes doable, as well as representing a mechanically simple way to select certain gears. Without electronic control, selectring first, second, or any other gear requires locking out multiple aspects of a fully hydro-mechanical automatic transmision, which could potentially be very complicated. The first instances of electronic transmission control we see were automatic overdrive units, back in the 1950s and 60s. These were an incremental improvement on manual overdrives, and made cruising easier; lifting one's foot off the gas in a high gear was all it took to engage overdrive. In the 1970s, overdrive units became particularly important, because of the energy crisis and also new EPA rules requiring better automotive emissions and fuel economy. After overdrive transmissions became widespread, the next part of the drivetrain to be targeted for improvement was the torque converter-locking torque converters of course reduce turbulent and viscous losses and improve fuel economy and power delivery. Of course, in a hydraulic system, control of such a clutch is spotty and irregular, so a servo-operated electronic torque converter clutch offers more reliable and controllable lockup. The 1981 Chevrolet Camaro took advantage of this, with its revolutionary Computer Command Control system, which, in addition to electronically controlling torque converter lockup, also had a rudimentary closed-loop engine control system, adjusting the carburettor in order to improve the air-fuel ratio. This year of the Camaro was of course not particularly fast, since small-block V8s made about 160-180 hp in those days, but it was technically interesting: This was an electronic system that controlled not only (some aspects of) engine behavior, but also controlled (one part of) the transmission as well. Sources are inconclusive, but it seems that this Computer Command Control system blossomed across many Chevrolet models in the early 1980s.

Baby steps...

However, this C.C.C. system still only controlled lockup behavior, not transmission shifting, and at this point, manumatic operation would still be unachievable. That would require an automatic transmission that was fully electronically controlled. According to Manfred Schwab in his paper on electronically-controlled transmissions, the first microprocessor-controlled transmissions showed up in the early 80s, with the "first transmission with fully electronic microprocessor control of all major functions" being ZF's 4HP-22 transmission, a four-speed longitudinal unit that Schwab says came out in 1983. The 4HP included electronically controlled lockup clutch as well as electronically-controlled shift solenoids. However, Toyota, in a 1981 press release, claims that they developed the first microprocessor controlled automatic, also a four speed, longitudinal unit. Tentatively, I credit Toyota with the first electronically controlled automatic, but ZF's contributions to transmission development are many. Other manufacturers would follow suit, like Subaru's 4EAT transmission in 1988, Chrysler's 41TE Ultradrive in 1989, and GM's 4L60E and 4L60E transmissions from 1991. By the early 1990s, electronically controlled transmissions were well underway in being introducted to the public. Schwab reports that, in 1989, approximately 50% of automatic transmissions in Japan featured electronic control, but in the USA, less than 10% did. However, this would likely change quickly, as transmissions like GM's 4T40E and Ford's AXOD transmissions, which showed up in the early and mid 1990s, became more prevalent in economy cars. By the turn of the century, there were five-speed automatics in production, with six-speeds on the way, all electronically controlled.

So by the late 1980s, electronically controlled automatic transmissions were under development and were showing up in many car models, at least from the manufacturers which developed such transmissions early. Cars so equipped still featured normal shifters however, with the typical P-R-N-D-D3-2-1 layout; some gear selection was therefore possible, but not to the extent enabled by manumatic control schemes, and as such, the final barrier remaining until manumatic controls could be implemented was the shifter design itself, since electronically controlled transmissions were already incorporating driver behavior (throttle position and rate) as well as engine parameters into their logic.

An evolutionary step becomes a behavioral leap

Porsche was the company to make that final incremental improvement, that final change that would bring their manumatic system, Tiptronic, into the world. Venarca reports that the 1990 964 generation 911 was the first car to receive the Tiptronic system, with a manual gate in the shifter that allowed the driver to command shifts outside of the transmission's normal logic. That concept of the shift lever being "bumped" forwards or back, to control an electronic transmission, evolved from the Porsche Doppelkupplungsgetriebe, or PDK, dual clutch transmission, implemented in the 962 racing car in the mid 1980s. According to Alexander Stoklosa of Car and Driver, the PDK-equipped racing cars originated the bump-to-shift user interface, though their use of the PDK was purely to speed up shifts, not lessen driver workload, with the PDK reportedly being a difficult gearbox to use. Stoklosa writes that the 1990 911 was originally to get a PDK transmission, but following reliability issues, received a torque converter automatic unit instead, and was the first production car to feature a manumatic mode. Stoklosa mentions that this first Tiptronic system had its faults, such as a lack of downshift rev matching. However, this was ground zero for the installation of manumatic control schemes in production cars with torque converter automatics. After the precedent was set, other manufacturers would slowly follow suit, implementing their own manumatic systems through the 1990s.

At first, manumatic systems were limited to high-end models, perhaps being seen as a luxury option. Honda was the first to follow after Porsche, releasing their (Acura branded) "SportShift" system on the NSX in 1995. BMW released their first implementations of their "Steptronic" system in 1997-97 (the exact date is unclear), and the 1998 Nissan Skyline (only released in right hand drive Pacific markets) was the first Nissan to feature a manumatic system. The NSX was the first car to see a steering-column mounted "paddle shifter" (see the NSX Prime forum article), and the 1998 Skyline curiously featured steering wheel rocker switches in addition to a shift lever gate. However, most of these models were fairly unobtainable for the average person, and adoption of manumatic controls in economy cars and mass-market consumer automobiles was slower. Rik Paul writes for Motor Trend in 1995 that the 1996 Eagle Vision, with Chrysler's then-new "Autostick" system, was the first "normal" car to receive a manumatic system. This would use the aforementioned 42LE Ultradrive transmission. Paul mentions that the 911's Tiptronic and the NSX's SportShift systems both cost over $3000 as options, with the Autostick option for the Eagle Vision coming substantially cheaper, and standard with the Vision TSi. The Autostick system used detents to the left and right, instead of forward and back, for shift command stick movements, a model that would eventually migrate to many cars from both Chrysler and Mercedes during the Daimler-Chrysler years. Even now, the Dodge Journey features the same mechanism. We should credit Chrysler however, and particularly the Eagle marque, with making manumatic mainstream: The Eagle Vision would set an example for future budget-friendly American "sports sedans" that would become quite popular in the 2000s. In a way, because the Vision was built on the longitudinal front wheel drive LH platform, which would be adapted into the rear wheel drive LX platform, it could be considered the grandfather of the Dodge Charger, which enjoys so much success today.

In the 2000s, manumatic modes would be implemented in many more cars, and would become nearly-standard by the 2010s. GM would introduce the system in 2006 with Saab's "Sentronic" system, using the Aisin AF40-6 transmission, as well as in the Chevrolet Malibu Maxx SS and Saturn Aura XR as "Tap Up/Down" and "TAPShift" respectively. The 1997 Prelude and 1998 Acura TL were Honda's first mass-market automobiles to see their SportShift system, while Ford would wait until 2003 to build a car featuring a manumatic system, the Lincoln LS, with a five speed automatic featuring "SelectShift." By 2020, nearly all new torque converter automatic-equipped cars have some sort of manumatic mode, though some manufacturers are moving more heavily towards continuously variable transmissions, which, by their nature, generally do not feature discrete ratios, and are therefore somewhat less suitable for manumatic systems.

That said, many CVT-equipped cars do have options for manumatic-like shifting modes, where the driver can use paddle shifters or the stick to sequentially shift between various fixed ratios: A kind of "fake" manumatic, if such a term can even be applied. Additionally, some manufacturers never strongly adopted manumatic options for their automatic transmissions. Many Ford models produced with automatic transmissions don't receive the SelectShift system, or have it as a feature on a higher trim level. Many Honda vehicles produced with electronically-controlled automatic transmissions, like the author's very own 2006 Civic, do not feature a manumatic mode, even when many Acura models do (including the Acura CSX, a Canada-only version of the eighth generation Civic.) Is this a bad thing? In my subjective opinion, yes it is, but to many drivers it simply doesn't matter.

What do car fans think about manumatic systems?

Car enthusiasts are of course not a monolith, and have widely varying views, but I have found that most opinions on manumatic systems boil down to one of just a few general categories. One is the dismissive, purist stance, seeing manual transmissions as the only "true" or "canonical" way of selecting one's gears, with manumatic systems being at best a pale imitation and at worst a useless toy. Another position is that of ignorance or refusal, believing that automatic transmission shift logic is sufficient to handle all driving situations without any driver shift command input, and that manumatic just doesn't matter for driving an automatic car. Some enjoy their manumatic-equipped transmissions, appreciating that they offer the choice of both hands-free automatic driving, but also manual shifts for when they really matter. Interestingly, the biggest sticking point that many seem to have with manumatic-equipped transmissions is the idea that manumatic shifting is a replacement for manual transmissions, or a competitor. Many times, discussions of manumatic transmissions include someone complaining that a manumatic "will never be" a manual, framing the introduction of the manumatic control scheme as a replacement for manuals in general.

However, we have seen that manumatics were never introduced to be a replacement for manual transmissions: Instead, they were the result of years of incremental progress, first through transmission technology and then through control schemes, finally culminating in a relatively small final step that would bring us the manumatic transmission as we know it now. The technical history of manumatics makes it clear that they were never meant to be manual transmissions. Rather, the manumatic system is simply a more elegant, user-friendly replacement for the various D-D3-2-1 gates and overdrive toggle switches and shift mode control switches. The late '90s Jaguar XK8's shifter was the ultimate example of this, with a bizarre U-shaped track, with a detent for every single one of the transmission's gears. We should see manumatic modes not as a new beast entirely, but rather as the logical conclusion of advances in automatic transmission design. Manual transmissions are not dying out because manumatics are a silver bullet, they're dying out because they don't sell. Tragic as it may be, that is one of the consequences of a free-market system: Only that which sells, survives. On the bright side though, automatics are getting better all the time, and now there is a massive variety of automatic transmission sports cars, with paddle shifts and fast-shifting gearboxes. Manumatic systems are here to stay, and they will probably last as long as the internal combustion engine itself does.

However, we have seen that manumatics were never introduced to be a replacement for manual transmissions: Instead, they were the result of years of incremental progress, first through transmission technology and then through control schemes, finally culminating in a relatively small final step that would bring us the manumatic transmission as we know it now. The technical history of manumatics makes it clear that they were never meant to be manual transmissions. Rather, the manumatic system is simply a more elegant, user-friendly replacement for the various D-D3-2-1 gates and overdrive toggle switches and shift mode control switches. The late '90s Jaguar XK8's shifter was the ultimate example of this, with a bizarre U-shaped track, with a detent for every single one of the transmission's gears. We should see manumatic modes not as a new beast entirely, but rather as the logical conclusion of advances in automatic transmission design. Manual transmissions are not dying out because manumatics are a silver bullet, they're dying out because they don't sell. Tragic as it may be, that is one of the consequences of a free-market system: Only that which sells, survives. On the bright side though, automatics are getting better all the time, and now there is a massive variety of automatic transmission sports cars, with paddle shifters and fast-shifting gearboxes. Manumatic systems are here to stay, and they will probably last as long as the internal combustion engine itself does.

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