Transmission designs

Transmission designs

Different Designs

The drivetrain of an automobile is in principle always constructed the same way: the torque is transmitted from the engine via the clutch and the transmission (for example also an automatic transmission with torque converter) to the axle differential gears and finally to the drive axles and wheels. However, the transmission designs that can be used vary depending on the manufacturer and size of a car:

ManualShift 6MTT480

Transmissions for Transversal Applications

This refers to a transmission mounted transversely to the driving direction. Transmission and axle differential are mounted in the same housing. Therefore the engine compartment can be designed relatively short. Such transmissions for transversal application are widely spread and can be found in about 80 per cent of all cars worldwide. In some specific cases this layout can be found on rear axles as well.

PowerShift 7DCI700

Transmissions for Inline Applications

In this layout the transmission is mounted in the centre tunnel of the vehicle along the driving direction. The engine is arranged longitudinally along the front axle and flange-mounted to the transmission. The transmission drives the axle differential of the rear axle via a cardan shaft. Inline transmissions are mainly used in bigger and high-performance cars, they have a market share of approximately 10 per cent.

PowerShift 7DCL750

Transmissions for longitudinal application

This transmission design is also mounted longitudinally to the movement direction. Other than inline transmissions, it can be mounted either by the front or rear axle. Since the axle differential is integrated into the transmission housing, the installation position determines the axle being driven. Transmissions for longitudinal application are usually used in sophisticated car segments and for sports cars. The market share of this design is around 5 per cent.

Regardless of the design, all transmissions use gear wheel gradations on a countershaft that reduces the rotational speed of the driven shaft and increases the available torque. Thus the various gear gradations can be very compactly built.

For starting and changing gear, at least one clutch is required (two in the case of dual clutch transmissions). The desired gear is engaged by means of a synchronisation unit.