Semi-automatic transmission- how does it work?

Semi-automatic transmission has been in existence since the 1930s but over the years, they have evolved with the advancement in technology. The semi-automaticcars right now are not what they were back in the day and are rare to find. This is because the current generation prefers the automatic transmission as compared to both the semi-automatic and manual transmissions.

So what’s the point of the semi-automatic transmission vehicles? Despite the name, the semi-automatic transmission is more manual than it is automatic since the one thing it lacks is a clutch and therefore instead of having pipes and cables, it has electronic processors and sensors for gearshifts. The gearbox in the semi-automatic is what you would find in a manual transmission vehicle although made easier for those who would rather do away with the clutch.

Read on to find out more info concerning the semi-automatic.

How does it work?

The semi-automatic transmission works just as the other transmissions do in that it uses kinetic energy so as to turn the wheels via the rotation of the input shaft and the different gears. A clutch is situated between the engine and gearbox to allow for this process to take place through engaging and disengaging the clutch.

Since, we mentioned that the semi-automatic does not contain a clutch pedal, the electronic processors and sensors are the ones in charge of engaging and disengaging the engine. The gear lever in a semi-automatic is marked with (+) and (-), where the (+) sign is used to change gears if the speed is picking up, upshift and (-) is used when speed is slowing, downshift.

In modern semi-automatic cars, you have the option to switch to using the automated gear lever which means that you have the (P R N D) controls where P is Park, R stands for Reverse, N for Neutral and D, Drive.

The control unit in the semi-automatic transmission is the one tasked with determining speed of the car, engine torque and the pedal position of the accelerator among other functions. The gearbox is therefore able to calculate the perfect timing for a gearshift accurately making the gearshift fast and smooth.

While it provides the driver with a great experience of both the manual and automatic transmissions, we need to look at what some of the positives are as well as the drawbacks.


Fast and Smooth gearshift

Since the gearbox is equipped with a control unit, or computer system if you like, the precision at which it is able to detect a need for a gearshift makes that gear shift faster and more smooth than if you were dealing with a manual transmission.

Fuel Mileage

Semi-automatic transmission gives you great fuel mileage which is similar to manual transmission. It gives even better fuel efficiency due to its precision in gear changes. It’s better in fuel efficiency than both the conventional and automatic transmissions.

Energy loss

There is no energy lost should the torque convertors experience any slippage.


It is a good training car for anyone learning to drive a manual transmission vehicle as the learner will get to have an experience of changing gears without having to sweat over when/how to use the clutch.



Due to the complicated components used in the transmission, should they get damaged, are expensive to repair and in most cases people have opted to replacing the transmission instead of repairing. When it comes to maintenance as well, it will cost you more with a semi-automatic transmission.


Semi-automatic transmissions tend to fail and malfunction often so this can be a bit of an inconvenience because even after replacing the transmission, durability is not guaranteed.

Hills and slopes

This transmission fails the test when being driven on hills and slopes. This is because it lacks functions such as the Hill Hold Assist or the Auto Release.

Jerky Shifts

If you an aggressive driver, then expect to experience jerky shifts while driving.

Here are some steps to driving a semi-automatic car

Step 1

Place your foot on the brake pedal and insert your key into the ignition and turn it. Move your lever towards neutral and in case your car has paddle shifts then pull both of them towards you and that will place the car in neutral. Make sure that your foot is still on the brake pedal to avoid the car moving on its own as you engage gear.

Step 2

Between the two front seats, there should be gearshift marked with different letters and symbols. What you’re looking for is the (+) and (-) signs because that’s what you will use to shift gears. In other cars the (+) paddle is on the right while the (-) paddle is on the left attached to the steering wheel. This will be indicated on the dashboard to keep reminding you what mode your car is in.

Moving forward

To move forward, move your gearshift to D which means Drive and now disengage the car’s brake pedal by lifting your foot off of it.As you do this your car will automatically move forward.

Step 3- Reversing

If you want to move your car backwards, then with your foot on the brake while making sure that the car is on neutral. Shift into R which means Reverse and let go of the brake pedal. The car will start moving backwards.  To stop the car start applying pressure on the brake slowly until it stops and shift the car back to neutral.

Step 4- Engaging gears

Before you start engaging gears, you want to make sure that your car is in D mode. As you start moving forward, the vehicle will be in first gear. You want to make sure you move your lever to M which stands for Manual mode so that you can now take charge of shifting gears manually. Don’t start shifting yet but as the car starts to pick up speed, you need to be keen and start listening to the engine.

As you start picking up speed, you need want to make sure that you change gear accordingly. It is generally recommended to start upshifting when you get to approximately 3,000 RPM (Revolutions Per Mile). Should you feel that your engine sounds as if it is struggling to keep up then that’s an indication that you need to shift gears.

If you want to stop the car, then you need to apply pressure on the brake pedal and downshift to the first gear which will slow and eventually stop the car. Place your car in neutral, apply your parking brake and turn the key off to kill the engine.

Note: When accelerating it is not required that you let go of the gas pedal but when slowing down remember to ease of the gas for every downshift.

Neutral is not a gear and don’t treat it as such. It is rarely used since what it does is cut off the link between the engine and accelerator.

Hopefully those steps lead you to the grocery store and not to the emergency room. Not to say they aren’t accurate but you know if you’re horrible at following written instructions, then go enroll at a driving school and have your instructor carefully direct you. In case you’re wondering which cars have a semi-automatic gearbox, here are a few examples to get you started.

Cars with a semi-automatic transmission

Ferrari- Ferrari Mondial used a semi-automatic transmission first in the year 1993 using Ferrari’s own gearbox that had been in use previously in their Formula One vehicles. Shortly after in the year 1997, The Ferrari F355 got its first paddle shift transmission. They have however moved on to using the double-clutch system in all their new models.

Ford – The first automatic was introduced in the Ford 1970 Maverick 6-cylinder model which had a regular semiautomatic transmission meaning that a ‘driver had to move the selector between the forward gears’, but they later developed it to the SelectShift.

Opel – They produced an Easytronic semi-automatic gearbox and as is normal with most automatic vehicles, has two pedals, brake and accelerator pedals. However, there’s an added feature with this one and that’s the fact that it has an electrohydraulic clutch.


What’s the point of the semi-automatic transmission? Well after understanding this transmission a bit better, we strongly feel that inasmuch as it may have a few benefits, the fact that the transmission is known to always have malfunctions is quite off putting.

For that reason, we don’t quite see the point of its manufacture. However, not all is gloom because with the current technology, we are optimistic that some of the disadvantages seen here could easily be fixed. And should this happen then the semi-automatic transmission might be a game changer.

Having the option of experiencing both the manual and automatic transmission, added with the great fuel efficiency, precision and accuracy, speed and smoothness of gearshifts, we think that this is a potential must have in the near future.



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