Would I be correct in saying that you have a you have a 4x4 with a 4l60e transmission? That's what it looks like from the photo.
The first picture could be from a number of things, but my guess is that its engine oil and not transmission fluid. I think oil leaking from the engine is being blown back onto the trans from maybe a valve cover or something.
Now when it comes to the second picture, it looks like your output shaft seal is leaking; in order to fix this, all you have to do is pull the driveshaft, pry the seal out, then press in the new one using a hammer and some sort of tube that fits around the metal ring (I've had to do this at the side of the road before after the seal came unseated and got shredded).