The motor is off the car on an engine stand. So i flipped it upside down, took off the old pump and shaft. The new on looks like it just sits inside a hole and kind of dangles there, the other end of it fits inside a groove on the oil pump. IS that correct. I don't see how this works. Shouldn't there be grooves or something on the other side of the oil shaft, does the shaft spin or pump. Would hate to start a motor without the pump working.