2003 Liberty makes humming noise and vibration during deceleration
I have a concern regarding the noise being generated when i decelerate. The car runs perfectly fine if i keep it at low speeds like when I drive around the neighborhood. When I manage to get it up to about 30+ MPH, when i let off the gas, I can hear a faint humming sound. When i put my foot back on the gas, the humming goes away. As I decelerate, the humming becomes a bit more noticable, and if i break, it becomes very noticable, and i can feel a slight vibration in the petal and in the floor when it gets down to about 10 MPH to when it stops. I rarely get to real highway speeds, but i'm pretty sure the last time I did, I heard the same faint humming while driving at a constant speed of 65-70 MPH. Though, like I said, none of it happens if i keep the car at slow speeds, so I'm pretty confident it doesnt have to do with the brakes or wheels.
Recently (3 weeks ago), I had the transmission fluid changed, and found that it was about a half qt low in fluid, which i've since added. I've read that it might be the u-joints on the driveshaft, but if it was them, wouldnt the vibration occur during acceleration as well, or at least every time the car was decelerating?
Can anyone relate to this problem, or have any recomendations of what might be the cause?