Engine light is on but no codes

I'm completely lost! My check engine light is on and was
saying that I had a bad o2 sensor. But now, it won't throw
any codes at all. However, when I push on the gas, she'll
go but once she hits 2 rpms she just sputters and jolts.
Also, checked tranny fluid and it was fine but I just noticed
that tranny fluid is all inside driver side wheel well, on the
inside of my hood, ok the outside of the grill, all over
inside the hood actually, and when I looked under the car,
it appeared to be leaking all over under the drivers side.
HELP PLEASE!!