So beschreibt das Siemens:
An HST housing axle driving apparatus for a small-sized running vehicle, such as a tractor, in which an axle casing is divided into a left-side half axle casing and a right-side half axle casing. In one of the left- and right-side half axle casings are disposed a hydraulic pump provided with a vertical pump shaft and a hydraulic motor provided with a horizontal motor shaft. In the other of the left- and right-side half axle casings are disposed a speed reduction shaft and a differential gear unit, so that a driving force is adapted to be transmitted from the vertical pump shaft to the horizontal motor shaft.
Was allerdings Dein Teil damit zu tun hat ist mir unklar.
Vielleicht sowas wie ein Typenschild
Gruß Octavian
P.S.: Ich hab' keine Ahnung was das sein könnte.