A safety device (12) is disclosed for use in a hydraulic pump system (10). The device includes a generator (20) mounted between the power take off (14) and the hydraulic pump (24). Any time the hydraulic pump (24) is operated by the pto shaft (18) of the power take off (14), the generator is also powered to generate power to operate an audible alarm (28) such as a horn, siren or bell to warn the operator of pump operation. In a second embodiment, hydraulic pump system (100) uses a standard, readily available alternator (102) to generate power to operate the audible alarm (28). A selector valve (202) can be positioned between the pump (24) and lift cylinder to divert hydraulic fluid to a reservoir if the pump is inadvertently activated. The selector valve (202) can be operated manually by the driver when the vehicle is about to be put in motion by operating a control valve (212) or automatically by sensing vehicle motion, such as done by sensors in an ABS brake control.