2000 springer softail. I was changing my oil and wasn't thinking and drained whatever oil was in the front of the bottom end. I was on the right side and instead of the opening up the back drain plug on the right side I opened up the one on the front on the right side. Just a little came out. What is this for? This isn't the primary case on the left side. I changed the oil after figuring out that I did the wrong one. I looked through my book, but couldn't find it. What is this drain plug to?