It is the Steering gear box. It is the seal on the bottom of the unit. After it is replaced it is fine for a few weeks. Then it just doesn't leak, it blows out out the fluid comes out as fast as it can be poured into the power steering unit. I couldn't see how it could be the Power steering unit either, but then I didn't know if there is some kind of check valve or something else in the Power Steering unit that could build up pressure in the gear box.