I hit something while driving and I noticed that there is a black oily fluid leaking from under the engine cover. First it was only a little, but the next day, there was a lot. What is it? When I check the oil, computer doesn't say that it is low?? Maybe it's a transmision fluid? Any ideas.

 

Check the dipsitck. Its gonna be one or the other. In any case i wouldnt drive it like that.

 

I think you have cracked your oil pan. Put the car up on axle stands, take the belly pan off and find the dent.

Check your oil with the dipstick.

Don't drive the car until you find the source of the leak.