The invention concerns an engine-rpm-dependent arrest device to prevent non-permitted down shifts in motor vehicle gearboxes, comprising a pilot valve (1) and a control valve (2), both of which have two positions. The control valve (2) is switched into one position by the pressure acting on the surface (36) of the control-valve piston (31), when this pressure exceeds a given pressure produced by a low-pressure pump (20) operating in dependence on engine rpm. The control valve (2) is only in contact with the pressure medium conveyed by the low-pressure pump (20) and controls the large end surface (40) and the annular surface (41) of the stepped-design pilot-valve piston (38). If, with a high gear engaged and motor rpm above a given limit, the gear-shift valve (7) is shifted to its low-gear position, the pilot valve (1) prevents pressure acting on the low-gear activation device (15). At the same time, pressure continues to act on the high-gear activation device (16), thus keeping the gearbox in the high gear.