I have a 5 speed, had the clutch replaced last Dec, then had a leak repaired in February. While driving on the Interstate at about 65MPH, I heard a loud noise that sounded like a blowout. It then rattled like I was dragging something metal. When the car is in idle it does not make this noise, but in 1st, 2nd, 3rd, and 5th gear it makes the noise. In 4th gear, it makes a whining noise. My husband has determined it comes from the transmission casing. Any ideas on what it is, so I can get an idea on how much this will cost us?