An Automated Manual Transmission or Semi Automatic Transmission allows manual gear changes and uses a clutch but
facilitates the gear changes without a clutch pedal.
It's basically a computerized manual transmission with somewhat automatic
controls/shifters plus an ability to manually shift between gears.
The gears are not laid out in an "H" pattern as in a traditional manual but gear changes are achieved via an
"up" and "down" or "+" and "-" interface on paddle shifters and/or on the gear lever.
How it works is via an electro-hydraulic mechanism in place of clutch pedal and a physical cable to disengage the
clutch and allow gear changes.
The electronics/ECU can also interface with the engine's electronics and
perform rev matching before engaging the clutch again.
An automated manual has a direct connection to the engine unlike a torque converter but is much easier to use than a
conventional gear shifter and clutch pedal.
The gear changes are generally quicker as the clutch can be disengaged and re-engaged faster via the electronics and
launch control can be easily incorporated into the transmission.
Although it's a manual by nature, it can also function as an automatic by using the computer/electronics to shift
between gears automatically.
There are some disadvantages such as a semi automatic is usually more expensive and maybe slightly heavier than a
comparative automatic or manual.
The gear changes are not as smooth as a torque converter automatic (or even manual in some cases) and the regular
transmissions are generally better suited for regular driving and driving in traffic.
Automated manuals can be made for a variety of platforms and found in a variety
of vehicles including sports cars, busses, trucks and even some economy cars.
Most sports cars however, use dual clutch transmission which is a type of
automated manual transmission that uses two clutches to further increase performance.
Performance oriented cars that still use a single clutch semi automatic are the Lamborghini Aventador and Aston Martin
Some vehicles with semi automatics function as automatics as default with an option to change gears (sometimes via a
sport mode) but vehicles such as supercars may only function as
The automated manual transmission (dual clutch included) has become very popular throughout the automotive industry as even
transmission giant ZF makes a semi automatic 8HP transmission.