Sequential Gearboxes

A sequential gearbox is largely found in motorbikes and racing cars, so it’s not surprising if you haven’t heard of it, or don’t know much about it. At Automatic Man, we perform gearbox repairs for all kinds of transmissions. Having already posted blogs about automatic gearboxes and semi-automatic gearboxes, it only seems right that we explore sequential gearboxes too. 

With over 20 years of relevant industry experience, a trusted reputation across West London and a real passion for quality, we don’t think there’s anyone better to write about one of our areas of speciality. In this blog post we’ll be covering everything from “what is a sequential gearbox” to “sequential gearbox repairs”, so fasten your seatbelts and we’ll drive right in. 

What Is A Sequential Gearbox?

A sequential gearbox is, as the name suggests, a kind of gearbox. It is suitable for both manual transmissions and automatic transmissions, and operated via a traditional stick or by paddle shifters. Paddle shifters allow for quick gear changing, and so are commonly found on sportier cars, as they mean that you don’t need to take your hands off the wheel. 

What Does “Sequential Gearbox” Mean?

It’s name comes from how it works, which we’ll get to in a minute. In the simplest sense, a sequential gearbox gets its name because the gears must be selected in order. The gearbox doesn’t allow for skipping gears, as with a traditional manual gearbox, and so you must go through each of the lower gears and work your way up. For example, to get into third gear you must start in first, and move into second and then third. This removes a lot of the potential for human error.

What Does SMG Stand For?

This far into the blog post, you might have guessed this already. SMG stands for sequential manual gearbox. Although sequential gearboxes can be found on automatic cars, it isn’t as common. SMGs are found in a range of different makes and models. The first SMG was used in 1990, in a Peugeot 905 Group C sports car. The most recent development in vehicles using an SMG is from NASCAR, who will be introducing the Gen-7 car in 2022, which will have 6 gears.

How Does A Sequential Gearbox Work?

The sequential gearbox is made up of 7 core components:

  • Sequential transmission
  • Gear selector fork
  • Selector pin
  • Selector shaft
  • Sequential gear selector
  • Multi-plate clutch
  • Dog clutch 

When the driver puts the vehicle into first gear, the gear selector rotates the selector shaft. This moves the selector pins, which move the selector forks. The corresponding selector fork will engage the dog clutch to first gear. The process is repeated as the driver moves upwards through the different gears. 

Advantages Of A Sequential Gearbox

  • Safety: By having to go through each of the gears, you mitigate the risk of dropping into the wrong gear- an act that could have serious repercussions, especially when driving at high speeds.
  • Clutch Optional: The selector shaft means that there is no need for the vehicle to have a clutch. This allows you to shift gears more quickly, and to focus more on driving. 
  • Speed: As you might be able to tell, the real advantage of an SMG lies in the speed that it offers- which is why they’re often used in motorsports vehicles.

Disadvantages Of A Sequential Gearbox

  • Expensive: Most vehicles fitted with an MSG are expensive, especially if you want a newer or flashier make and model. 
  • Noise: This kind of gearbox has a reputation for being incredibly loud, producing a whining sound that is either loved or hated, depending on who you are speaking to and how much they love cars.
  • Operation: There is a reason that the SMG is typically found in sports cars: it isn’t well suited to driving slowly. Many people find that for everyday driving, it’s “clunky”.

Sequential Gearbox Repairs

A sequential gearbox offers a longer life for the transmission and its related components because of the way it operates. However, like all gearboxes, it sometimes requires maintenance and repairs. This is because it is an essential element of your vehicle that is being used every single time you turn on the ignition. 

There are different types of sequential gearboxes, dictated by the vehicle that it’s in. For example, a BMW SMG differs depending on the model of the BMW, and this differs again from the Magneti Marelli sequential gearbox system that is found in Ferrari’s and Alfa’s. These subtle design and operation differences require a similarly nuanced approach to repairs- it’s always best to seek out a gearbox specialist, so that you can be assured that your vehicle is in safe hands. 

SMG Repairs With Automatic Man

At Automatic Man, we have extensive experience in servicing, repairing and reconditioning all kinds of gearboxes, including SMGs. Our wide range of services include free smg gearbox diagnostics, and our highly-trained engineers are confident in understanding and working with all vehicle makes and models. 

Our SMG repairs are underpinned by a wealth of industry experience, and an unmatched knowledge of vehicles and their inner workings. We have been operating in West London for over 20 years, and during this time we have developed a reputation for credibility, transparency and engineering excellence. 

If you’re interested in our gearbox services, or would like some more information on the vehicle solutions we can offer, then please don’t hesitate to get in touch. A member of our friendly, customer-first team will be happy to help in any way possible. Contact us today by phoning 020 8740 1020 or emailing [email protected].