Hey guys I have a problem and I need answers ASAP. So yesterday I ran my truck for about half a tank to get the bearings in the clutch broken in. When it stopped I looked at it and I noticed that there was fuel on the back of the chassis and on the rear brake pad. I also noticed that there was some oil-like substance on the engine. this was also the first time running my truck with the fuel filter on also.

Here are my questions:

1: What is the oil-like substance?

2: How did the fuel get on the back of the chassis?

3: Where did the oil stuff as well as the fuel come from?

4: What can I do so this won't happen again?

5: Why did this happen?