A mechanism is disclosed for controlling the vertical position of the transport trailer floor of a heavy trailer bearing vehicle having a pivoting air spring suspension system such that the transport trailer floor maintains a fixed position level to an adjacent dock platform when parked for loading or unloading. The first engagement means being connected to the second engagement means via at least one first joint being in form of a pivot andor at least one first spring means in order to be at least partly displaceable relative to the second engagement means, and a method using such a tool. Speed information may also be determined by the location management system, or the subscriber may be prompted to input a particular mode of transportation, or generally indicate their speed. The applied pressure or flow may be determined from the set slip, and occurrence of a set slip allows the occurring pressures to be determined. Flux return portions are disposed axially adjacent the disks at each end of the disk stack.