A power take-off unit is connected to a power take-off gear/port on a concrete mixing truck transmission, the power take-off unit being driven by the engine so it is always providing power as long as the engine is running. A hydraulic pump is connected to and driven by the power take-off unit. Hydraulic lines connect the pump to a planetary drive assembly for the concrete mixing drum; the drum itself is capable of receiving only a small/light load of concrete, in the range of two to five cubic yards.