Over the past 50 years, we’ve seen building modified cars go from a purely mechanical endeavour to one that blends modern electronics with internal combustion. Sure, carburetors and mechanical fuel injection may have character, but the capabilities unlocked after integrating modern electronically controlled parts into older cars is astonishing. Case in point: It turns out that the new hotness in everything from sports cars built for time attack events to pro touring muscle cars is a gearbox borrowed from BMW M Cars of the late 2000s and early 2010s. This might sound like a weird matchup, but it actually makes perfect sense.
See, these intrepid builders aren’t just swapping any old gearboxes into their cars. They’re swapping dual-clutch transmissions into cars that never came with them, bringing modern performance to vehicles that may have otherwise never come with a performance automatic option. Specifically, they’re swapping in the Getrag GS7D36SG, and here’s everything you need to know about this gearbox conversion.
The Getrag GS7D36SG is a seven-speed dual wet clutch transmission found in all manner of fast BMWs including the E9x M3, F10 M5, F8x M2, M3 and M4, and the F06, F12, and F13 M6. As far as longitudinal dual clutch transmissions go, it’s one of the more common units, and it’s a remarkably stout one. Of course, it also helps that these transmissions often come attached to engines that frequently suffer from problems, ensuring a certain supply of them on the second-hand market. That E90 M3 might’ve spun a rod bearing, but the gearbox is still good.
Alright, so you’ve pulled a GS7D36SG out of a wrecked or blown up BMW, and you have it in front of your project car. Now what? How are you going to mate it up to your engine of choice? Fortunately, adapters are out there from brands like PMC Motorsports and Seems Legit Garage. Want to bolt this gearbox up to an LS V8, a Honda K-series inline-four, a Mazda 13B rotary engine, or a Toyota JZ inline-six? No problem, kits are out there.
Of course, getting the transmission mounted in the car is only half the battle. Modern transmissions require modern electronics, and that’s where HTG Tuning out of Poland comes in clutch with a standalone gearbox controller that works nicely with this seven-speed DCT. Not only does it support automatic learning to speed tuning along, HTG’s wiki has detailed instructions for wiring and setup that seem remarkably easy to follow along.
It’s also worth mentioning that the easy work of a DCT swap stops here. You’ll still need to have a driveshaft fabricated, you’ll still have to figure out transmission mounts, and you may need to bash or even cut your transmission tunnel to fit this seven-speed DCT in your car. You’ll even need to get around the parking lock inside the DCT, although that can be done with a $60 part.
However, once everything is said and done, swapping a BMW-sourced Getrag GS7D36BZ into your project car will give it automatic convenience and shift times of about 50 milliseconds. It’s a neat option for pro touring builds, people who are big into time attack, and builds where you want to keep from falling out of boost on every shift. Is it for everyone? No. From the cost of acquiring the transmission to the cost of the supporting parts, this sort of swap will cost thousands. However, if you’re looking for a no-holds-barred solution, how much does the price tag matter?
To get a sense of how wide the scope of these BMW DCT swaps goes, here’s a video from racing driver Jackie Ding covering a K24-swapped, DCT-swapped Honda S2000 track car. It’s pretty mental, and you’re going to want to check out the in-car footage of this thing devouring Gingerman Raceway.
On the complete other end of the spectrum, here’s YouTuber The Oldsmobeast kicking off a GS7D36SG swap into his LS-powered Oldsmobile Cutlass. In this video, he makes some great points — this gearbox is cheaper than a racing-spec sequential gearbox, more streetable than a sequential, and offers fast, manual control of shifts.
How about a 900-horsepower turbocharged VQ37-swapped S14 240SX with a BMW DCT? That Racing Channel has some great coverage of this insane build, and man, is it ever a monster. Can it just get the win over a modified C6 Corvette ZR1? Yes, yes it can.
It turns out that swapping a BMW gearbox into just about anything imaginable isn’t that crazy, so long as it’s the Getrag GS7D36G. Sure, a manual may be more a purist’s choice on a winding road, but for track work and heavy traffic, there’s definitely huge appeal to a DCT. Expect this trend to only grow in popularity as more and more automotive subcultures catch onto it, because the momentum it’s built over the past few years has been staggering to watch.
Photo credits: BMW, HGT Tuning
Top graphic images: The Oldsmobeast/YouTube; BMW
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I’m mad that this blog post wasn’t about the ZF 8-speed. For shame.
Muscle cars get a DSG, Old BMW’s can get a real manual thrown in. Everybody wins!
I’m betting that controller is over 2k. So this could be anywhere from 4k to 6k swap. may be worth it for some.
The HTG controller is €1,300.00 on their website.
No idea how many taxes or shipping you’d have to pay on top of that to get it to where ever you are.
A slushbox? Eww.
Nope – It’s a DCT if you read the article.
If it doesn’t have a clutch pedal and mechanical lever to choose the gears, it’s a slushbox.
No, the reason slushboxes are called slushboxes is because of the torque converter present in your average automatic that essentially connects the power to the wheels through a fluid. Hence the term slush.
The “slushbox” refers to the torque converter aspect of the transmission. A DCT doesn’t have a torque converter, therefore, it doesn’t fall into that category.
Slushbox doesn’t even apply to modern torque converter autos like the ZF 8-speed. BTW, you can put a clutch pedal and a lever on a ZF 8-speed via the Turbolamik TCU.
It’s a joke, I’m a stick shift snob. Anything that’s not a manual is a slushbox.
I clicked this article hoping it would be about a manual BMW trans swap and now I’m sad.
Another increasingly popular swap is the zf 8hp**. Almost as fast shifts without the potential DCT headaches. Way easier to find used.
TJ and Mac on YouTube – one of the guys has put ZF8hp’s into 3 of his cars – S14 drift pig, a 79 Series LandCruiser and a Chevy K10 with a Cummins!
They’re becoming more and more popular as a conversion, as Thomas mentioned above – no shortage in cooked BMW’s.
The only “shiftable automatic” I’ve actually liked. Most of them drive me crazy, and I’ve heard even the ZF 8HP implementations vary, but the one in the F-type I rented was really quite good. Quick, consistent, and did as it’s told.
This would be so bad ass with a tactile shifter that had the same tension and breaking force as a sequential race box. The novelty of a sequential box without the cost or short service life. There are some amazing racing sim shifter units. I bet that could be adapted pretty easily.
Interesting. Would have thought this was going to be the ZF8 because its such a good and ubiquitous transmission.
Add some BMW to a functional car? Nope. From what I have seen of my friends who own BMWs when they work they are fabulous. When they stop working, give up.
…You do realize that Getrag is not BMW, right? They’re a transmission manufacturer that a large number of brands use or have historically used.
Gertrag may have made it but if it came out of a BMW it’s got BMW cooties. If its such a common transmission it shouldn’t be hard to find one out of something without cooties.
It’s not a common transmission. It was common amongst BMWs. Getrag is a common transmission manufacturer. Frankly hope you’re joking with the idea of BMW cooties, because I cannot think of any idea more childish…
Does this help?
/s
Came to say this. Getrag and ZF are independent of BMW. Really gives BMW credit where credit isn’t due. Imagine calling a manual a “Camaro 6 speed” while referencing the Tremec T56 (which was derived from the T5, used in both camaros and mustangs in the 80s)
German cars combine some brilliant engineering with some terrible over complication. The trick is selecting what you want, then swapping it into another car.
I’m hoping to swap Mk60E5 ABS out of an E9x series BMW into my Miata. I’ll be far from the first person to do so.
An ABS system from one car to another? That’s interesting. Is the BMW one adjustable or something? More sensitive and a stronger overall braking force (maybe smoother in the pedal) like a GT3 ABS system or something? Are there other options you can compare to either OEM or Aftermarket that are like this and aren’t literally racing units that would require either connections, a shitload of money, or both to acquire and retrofit to a custom build?
I can’t give you specifics on why this particular system became the darling of people looking to swap ABS over other cars, other than it’s extremely effective and readily available. Some reflash and recalibration is available but it’s very much in the phase of people still figuring out the details. Most people swapping the Mk60E5 simply go for a bare minimum install.
The “regular” Mk60 system was used on E46 M3s, and is still available to be purchased as a motorsports system. That system is specifically called out in some racing rule books as the only system that is acceptable to be added to a car and is extremely modifiable. Used units are pricey, which drove grassroots people to the Mk60E5.
Because ABS is a critical safety item, it has to have a very soft failure mode and keep working as best it can regardless of if it loses communication with other modules. You can’t lose ABS because the communication with the ECU or TCU is lost, for example. That helps when you’re ripping it out of one car and installing it in something like a 1960’s muscle car.
That point was made in the article. You know, when it mentioned that the reason why these transmissions are so readily available is because there’s so many BMWs that don’t run anymore and have no hope of being worth fixing. But since the transmission is built by Getrag and sourced by BMW it doesn’t suffer the same catastrophic failures of the rest of the power train.
I’ll be honest, I don’t see a point to the DCT when the ZF8HP exists.
Even the drifting world has embraced it. They even figured out how to “clutch kick” it by setting up a virtual clutch via a switch. They also have launch control, sequential shifters, and a whole host of features.
8speed.au is even offering a turn-key swap for R35 GT-Rs that retains the AWD.
The aspiring hot rodder that wants the coolness of flappy paddle control had best be aware that there are some differences between the BMW boxes. The 335is DCT has a 1:1 top gear and a deep 1st gear. The final drive is 2.56:1. The M model has a 0.67:1 top gear and similar spacing down to first. The different top gear will affect your choice of final drive. The 1:1 top gear will slow down the driveshaft and make it less prone to vibrations.
I love this because almost nobody talks about drive shaft speed. It’s why I hate even the concept of double and triple (or more!) overdrive transmissions, almost regardless of how many gears they have. It’s even worse once you consider the range of available rear-end ratios (really for any differential carrier/size) vs tire size (more applicable to offroaders, though).
It’s even worse, still, when you also factor in high RPM engines and cannot use the resultant top speeds of the longer end gears, with the gears being too long in general to take advantage of the high RPM/low torque engine.
I was first introduced to this concept by the Allison “World” 6 speed big rig automatic. It had a .50:1 top gear, but you couldn’t pair it with an engine that redlined over 1800 rpm on a conventional truck. The drive shaft would exceed the critical speed for that length.
Oh wow I actually thought this was going to be about the ZF 8-speed auto.
The ZF8 made the DCT obsolete almost overnight
And it is in millions of Stellantis vehicles
Sort of. My understanding is that V6 CJDR vehicles often used a license-built version of the ZF8 from Chrysler, while the HEMI models used the actual ZF8. I am not sure about the Hurricane cars.
That was my thought. The ZF8HP is on my list to swap into my w126 at some point.
I was thinking the same. I’ve heard people are swapping ZF-8 speeds into old off roaders like land cruisers and older Jeeps that originally came with 3 and 4 speed autos.
It was the auto that convinced me to try it for my current daily in a BMW 335ix GT. It is a fantastic transmission.
What’s the average cost for one of these swaps?
Boom! LS/DCT swap the world.
This is what I love about car culture; modding and the experimentation of swapping parts around. More stuff like this.
So…where do manual diehards fall on this? I’m all for it! For me, machines are made to be tinkered with.
I’m in to it. I think it would depend on the car/ build, though.
It’s more than a sequential for less money, I’d probably recommend this to anyone trying to build a winning race car in a class that allows it or who can’t drive a manual because they’ve lost a leg, an arm or both. I’m not in either group, so I’ll stick with the H-pattern for now, but I’m definitely not knocking on this swap, and would strongly consider it if a salt-water crocodile that sounds like a clock ate my left leg.
As long as I have two legs, my favorite transmission for performance driving will be a dogbox H-pattern. After that, the ZF8 (also in general). Then a sequential, then regular manual and DCT tied in fourth.
The reason I read this was simply for the science and technology aspects. I’m a diehard Manual Elitist for sure, but if I were to build a car strictly for speed, this would definitely be the way to go.
I think if the shifter is in the same spot and that polish system works fine with manual shifting full time, I could deal with not having to mash the extra pedal. the main thing here would be control of the gears. but it does sort of feel like cheating and strikes me as similar tot he FJ1300 semi automatic Motorcycles in that it just seems lazy and potentially more expensive to fix in the long run.
You can put the shifter wherever you want it, it’s just a switch. The shifter can be moved manually in the “sport” position, pulling rearward to upshift and pushing forward to downshift. In a BMW , the computers won’t allow a money shift, but who knows what an aftermarket controller will allow.
I had one of the FJR1300AEs. It was GLORIOUS. … Until I had to figure out how to bleed the clutch pack when I no longer had a clutch. There’s a service bolt for that, but you have to remove the whole swing arm.
Anyway. God, I loved that motorcycle and thought that if I ever wrecked it, the best thing for it would be to pull the engine into a Locost 7 build – shaft drive, sequential paddle shifter, 150ish HP and 100ish torque…
indeed, they were fast and smooth, at least the manual one I drove. the auto one seemed to lurch at low speeds. but still seemed like an innovative idea at least.
As a die hard manual driver, I’m into it. At heart I’m into mechanical stuff and this ticks the box and provides an interesting characterful driving experience.
I’d be interested in swapping a manually controlled CVT into something.
Absolutely hate it.
It isn’t just the dual clutch getting swapped, although that is common. All of the ZF series are becoming extremely popular as the CD009 supply from 350z dry up. The ZF handle power extremely well and are very available since all BMWs for around 3 decades have them. I plan on swapping a ZF 5 or 6 speed into my 99 Miata in the future in order to handle the increased power output I have planned. The swap kit is around $3000 and includes everything except the transmission. Once you have the kit you choose which one you want and it all installs. There are multiple Miatas in the 400-1000hp range running those transmissions and I have yet to hear of a failure. The ATS differentials are also picking up in popularity.
I hope you can get rid of the mushy shifter feel I’ve found in every BMW manual I’ve ever driven. Compared with a stock Miata shifter, you’ll be disappointed in the BMW boxes.
My M3 had a short throw shifter, and it still wasn’t as good as my stock NB Miata shifter.
They are sequential shifted automatics. Flappy-paddle, in other words.
The dual clutches are, but there is an entire range of ZF true manuals which are not and are traditional manuals.
We’re talking about two different things: the article talks about dual clutch automatics (which aren’t sequential, btw).
Turbotictac is talking about swapping a BMW ZF stick shift box, and my comments about mushiness were specifically for that.
The sequential automatics BMW offered were simply manual transmissions with an electronically-controlled hydraulic shifting mechanism. Those weren’t great, and it’s pretty common to convert those back to the standard manual transmission, like the E46 SMG cars for example.
My mistake on terminology, but my point was – why are we talking about sloppy shifter feel in an article about automatically shifted transmissions.
That is the biggest drawback I have heard. A lot of people do IRP shifters I have noticed. At that stage though it is purely for being able to handle the extra power output.
If I may give you a word of caution on that BMW trans swap…
Input From Other ZF Transmission Users on 65mph Driveline Vibration? – Miata Turbo Forum – Boost cars, acquire cats.
Kpower doesn’t have such a great reputation for quality these days.
I had heard of that, and I know Greg Peters at thecarpassionchannel had a similar issue and ended up finding a solution although I cannot recall what it was. Hopefully by the time I get to the point of doing it they will have sorted it out or a better option will have come up. I have a second turbo Miata, and I think I am going to try having the transmission built. There is a shop here in NC that upgrades them for about $1500. A friend had his 6 speed built by them and it has handled ~550 whp and ~450wtq for 3 years of heavy abuse drifting and it is still doing well. That’s about 200hp more than my daily makes so should be plenty.
What shop is that? Mine has 5 speed and I’m interested in getting more power to the ground, reliably and on the racetrack.
I have Mazdaspeed 6 speeds in both of my Miatas and a spare just in case. I prefer the feel of the 5 speed but the strength of the 6 speeds won out in my case.
https://jomotorsports.com/
Awesome, thank you!
I wonder if you can get parts for it. Getrag won’t sell parts for the 420G 6-speed in my 540i, probably at BMW’s insistence. The only choice is to buy a whole new unit from BMW.
Angry Bob and I are both angry about this
I remember this when I owned an e39 M5. Same with the ZF 5 speed auto in my parent’s e38 with it’s life time fill. No internal parts available and BMW refused to change the fluid and filter, which technically can be done.
Haven’t heard of this particular swap, but transmission swaps have been around for ages. Heard that the Ford 6R80 6 speed automatic is another new popular one.
Yeah, lots of folks are putting 6r80s and 10r80s in older cars. Sure beats an old C6 auto, if you’re boring and don’t want a manual
Very cool builds these. I don’t care that much about going fast so I’m happy to stick to a good ole fashioned stick but this is a cool swap for those focused on track times.
Good to see the options growing.
But can I fit one in my kids Barbie Jeep?
I believe the answer to that closely corresponds with the strictness of your definition of “fit” and your comfort with fabrication…
Sure, you just have to get your kid used to the idea they’re riding a transmission with a Barbie Jeep hanging off it. Also it probably won’t move anymore.
The mental picture of this will carry me through the rest of my day. xD
Grind Hard Plumbing, is that you?
Sounds like it’s popularity comes from the same rationale as the K- and B- Series Honda engines, and VQs, in that they were in a lot of vehicles, they have serious tuning overhead, and are reliable enough to justify the effort.
Given the complexities of DCT transmissions form a design and integration standpoint, having an option like this that’s this close to plug and play is pretty incredible. Like Thomas says, it’s not for everyone, but for a race car build, or just a “Can’t do manual for XYZ reason, but want something better than a 4L60” this seems pretty incredible.
It’s a tradition that goes back to the earliest days of “hot rodding”. (And I use that term very loosely.) From the flathead Ford, to early Buick and Cadillac V-8s, the Chevy Powerglide, and the small-block and LS engines, car builders have found components that were cheap, widely available, and GOOD, and then found ways to make them work well for whatever application they needed.