Automatic Transaxles and Transmissions by 
ASE Test Preparation - A2 Automatic Transmissions and Transaxles by This section will discuss the basic components and types of transmissions used in motor vehicles and what a transaxel is.
Transmission: Transfers engine power to the driveshaft and rear wheels or axles to the front wheels
Transaxel: a mechanical device which groups the roles of an transmission, the axle, and the differential into one integrated assembly.
Automatic Transmission (AT)
Uses a torque converter, planetary gearset and clutches to shift through a vehicle's forward gears automatically.
Manual Transmission (MT)
The driver selects all gears manually using both a movable gear selector and a driver-operated clutch.
Automated Manual Transmission (AM)
Employs a mechanical clutch; however, the action of the clutch is not controlled by the driver using the clutch pedal but is automated using electronic, pneumatic or hydraulic controls.
Continuously Variable Transmission (CVT)
Has a continuously variable drive ratio and uses belts, pulleys and sensors rather than gears to maintain a steady acceleration curve with no pauses for gear changes.
The basic components of a transmission are:
Planetary gear sets
A Transaxel contains the following components:
Shafts (input, idler, counter, etc)
Clutches and gears
Bearings
Components can vary between different transaxels
How Automatic Transmissions Work
Information and signs of a bad transaxel
