A CST gearbox comes in three parts: a supply unit, a first planetary gear stage and an output unit comprising a second planetary gear stage. The KP gearbox also comes in three parts. The supply unit and output unit are the same as the ones from the P gearbox, but the first planetary gear stage is replaced by a bevel helical gearbox unit. The KP gearbox design is available in a left-handed and in a right-handed version. It is also possible to mount the electro-hydraulic controller either inside or outside the supply unit.

The roller bearings of the bevel gear shaft are lubricated by forced lubrication via the built-in oil pump (usually responsible for cooling oil supply to the CST clutch). All other gearings and roller bearings are lubricated by means of splash lubrication.

Reduction ratios of 16:1 and 33:1 are available. The added M in the designation of the gearbox indicates that there is a pump unit with a separate pump motor in the supply unit, which works independently of the gearbox drive motor speed, and therefore ensures that the gearbox is continuously supplied with a constant flow of cooling and lubrication oil.

In contrast to the standard CST45, the electro-hydraulic controller is installed on a drawer and not fixed inside or sideways outside of the supply unit.

Like the CST45, this M version is able to sustain an input power of up to 800 kW/1,088 hp at a mains frequency of 50Hz ( ≈ 1,485 rpm) or 960 kW/1,305 hp at a mains frequency of 60 Hz ( ≈ 1,782 rpm). The permissible output torque is 450,000 Nm (max for 3 seconds). The rated continuous output torque is 170,000 Nm (i=33). The CST45 M gearbox can be used in combination with a HBT variable frequency drive.