teacherman 
2010 Nissan Altima Sedan 2.5 S 4dr Sedan (2.5L 4cyl CVT)
Noises?
 I only have 500 miles on it but notice when the car is full until ¾ a tank I here a sloshing noise that results in a knocking sound when slowing down, backing up, etc in the rear of the vehicle. The sound seems to be the fuel moving around the tank, but it is quite loud, and usually results in a few knocking sounds each time I hear it. I do not even need to be traveling at high speeds to hear this noise.  I have never heard anything like this on a vehicle and was wondering if anybody has had any similar experiences. I took it to the dealer and they hear the noise, but according to them it is common in the 2010 Altimas.