Ok so my differential was leaking, so I decided to reseal it and change the gear oil as long as I was going in there. I unbolted it, cleaned it up real nice, and used some of that..... i think its called permatex (black, they said it was what the Ford dealerships used). It seal up nice and clean. My problem came when filling it. I started to fill it up using the fill hole until the level of the gear oil reached the fill hole (I saw that some of the gear oil started to flow out) but I had only put 2 quarts when this happened (I read somewhere that the diff take 2.5 quarts). Now I know that when I change the gear oil in a manual tranny you're supposed to fill it up to the fill hole, but I'm not too sure thats the case with differentials. Any advice would be greatly appreciated.