Hello everyone, I'm hoping there is some serious expertise that can help me!

I have a '98 legacy outback. It has started shuddering when turning tight corners in both directions. I have also noticed a leak coming from dead center under the front hood. It looks like black liquid. There has also been a bad/acrid smell when starting the car, only noticable when you open the window or get out with the car on.

I went to a CV/muffler shop today and they jacked her up and inspected the cv boots- they were fine; and they were moving the wheel from left to right. Whatever was happening was fascinating to them as they called all the other workers to have a go. They said they didn't know what the problem was but they thought it was the differential.

I asked them what the leak was coming from - you could see that a flat piece of metal dead center was wet with a black liquid- they had no idea. Another piece of history: at the last oil change, I was told the transmission fluid needed changing (brown).

My questions are:
1) could this be a transmission problem; if there's a transmission leak
2) could this be a differential problem because of a differential oil leak?
3) In a Subaru Outback, if I get a transmission fluid and differential connected; i.e. will a transmission flush take care of everything?
4) I'm a student and can't afford to take this to a dealer, as was recommended- but I'm willing to spend up to $200.... otherwise i'm going to ignore it and hope nothign bad happens.!!!

Thank you!