I get a lot of negative comments and questions about the SMG gearbox in my E46 M3, but mostly from people who know nothing about them. So I decided to settle a few rumours by explaining a little more about it and why I opted to buy it.
The most common question I get is: “How many times has it broken?” usually followed by: “…and isn’t it about £3500 ($4700) to repair it when it does break?” Truth be told, yes I did once get a fault but it was a sensor switch on the side of the gearbox. The car ran in limp mode and it cost me me £18.75 to fix. Other than that, my SMG gearbox has currently survived for over 13 years and 140,000 miles, and has outlived an engine. I have a few friends who also drive SMG M3s, and guess what, theirs aren’t broken either!
The other big question I get from fellow petrolheads is: “So why didn’t you just buy a manual?” Now I don’t actually mind this question, because it enables me to talk about the gearbox’s benefits…
A few years ago I used to run a track day company, which offered advanced driver tuition to people who would bring their own cars to racetracks around the UK. The E46 M3 is a very common car of choice for track day drivers, and I was finding myself behind the wheel of at least two almost every week. I loved the manual, but the SMG felt so captivating with the paddles and fast shifting when on track. To me, it just felt more special than the manual, and that’s what prompted me to buy one.
Here are the Q&As that might help dispel a few scary stories.
Q: So what is SMG? It’s an auto, right?
A: First thing’s first, no, it absolutely, definitely is not automatic. The car does not automatically start moving forward when you take your foot off the brake pedal and the car does not shift up the gears for you if you forget to pull the up-shift paddle either. It really will just bounce off the rev limiter. SMG stands for Sequential Manual Gearbox. It’s actually the same manual gearbox that is found in the cars with a clutch pedal, but instead of having the clutch foot operated, it has the clutch electro-hydaulically operated via a pump and wired to computers. I want to say it’s similar to Lamborghini’s original E-Gear system, but I don’t know enough about Lamborghini’s system to say for sure (please chime in if you know). With the exception of a few software updates (and an extra gear), it’s also pretty much the same Sequential Manual Gearbox offered in the E60 M5 and E63 M6, but yet they don’t seem to get the same hate.
Q: Does it put down the same power?
Q: Is it as fast?
A: Independent testing actually suggests that in the most aggressive S6 setting, it shifts faster than even the fastest manual driver. However, real world comparisons tends to have SMG and manual cars neck and neck. So yeah, pretty much.
Q: Isn’t it much heavier?
A: No, not really. SMG cars weigh about 8kg/18lbs more.
Q: So why is it so hated?
A: Because when the system does have issues it’s headache inducing and wallet draining. However, problems are always easier to understand when investigated and broken down (as opposed to pointing in the general direction of an SMG and simply saying “all that is one big mess”).
The transmission itself usually holds up fine; it’s the hydraulic pump, the solenoids, and the relays that fail (and if you really want to get technical, the pumps tend to hold up fine, it’s the motors within that fail). These items can get expensive.
Q: But it’s not as involving and engaging as having a clutch pedal, right?
A: That’s all opinion. Would you think the 458 Italia and 991 GT3 are also cars that aren’t involving? I drive both a manual car and an SMG car and I find the SMG car to be fun in very different way.
So there you have it. Hopefully i’ve dispelled a few myths about the contraversial SMG M3. Any further questions? Feel free to fire away!
Q+A’s taken and adapted from here.