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this morning i left for school which is like 25 miles from my house. After i got off the freeway i stopped at a gas station to put gas in my car. Then after i got back on the street and i stopped to let a car pull out of a parking lot and as i did this i heard a weird nose which was kinda more like a rumbling sound. Im not sure where it came from. I immediately pulled into a parking lot and popped the hood and checked for any weird odors and didnt smell any. I checked under the car to see if it was leaking anything and it wasnt. then I proceeded to do a couple of laps in the parking lot just to see if i could hear it and i didnt, so i went to school which was less than 5 mins away and everything was fine. So i dont know whether i am over-reacting because the transmission which was an 01 got replaced with an 05 tranny. I was thinking it might have been that. Also im thinking that the noise could have been the fan turning on or maybe it was the brakes because I just bought the car and was planning to change them because they are completely worn out. Plz help, would be greatly appreciated!