1999 Ford Taurus Leaky Sensor and no motion...

There is what appears to be a sensor of some sort, just below the power steering fluid resevoir, on my wife's 1999 ford taurus. This sensor is leaking fluid at an alarming rate. I checked the tranny fluid 2 or 3 days ago and it was fine. Now when put into gear, you feel a slight "shift", as if it went into gear, but when applying the gas, the engine revs but the car goes nowhere. Again I checked the tranny fluid, and it still looks fine. Obviously the sensor needs replacing. My question is this,...what is this mystery sensor, what fluid is pouring out of it, and have we just burned up our tranny? The fluid is dirty so can't tell for sure what it is. I would guess tranny or power steering fluid, as I think I detected a red tint. Any help you can offer is gre[img:621b5cf3e7]http://www.2carpros.com/forum/automotive_pictures/547209_HPIM2014_1.jpg[/img:621b5cf3e7]atly appreciated.

Ed Hauk
EHauk3@gmail.com