So living in Wisconsin has the downfall of it's rather horrendous winters. At the same time it has helped bring to light a small problem with my car that I am not sure what it is. Whenever the temperature drops to below about 30 degrees, my car occasionally sounds like it is being dropped from a cliff like you hear in the old cartoons. I was wondering what that noise is. It will generally start sounding between 30-35 mph, any higher the noise just goes away. But if I start to decelerate, that is when the "bombshell dropping" sound begins. I have been told that it is probably my transmission and should just get it flushed. I have also been told that it is one of my axles. If anyone knows about this problem and could give me some insight at fixing it with costs, that would be wonderful.