Well i left for school a week ago and loaded up my car to full capacity. I have eibach lowering springs and the car looked very sag, so much so that the chassis setting light would come on everytime i hit a bump on my 1200 mile journey. Well with all the stuff out of my car the chassis setting light is off. But i formed a thudding noise, which sounds similar to riding around with a flat tire. I know the noise is coming from the rear but i am unsure of what it is. The sound is dependent upon speed. Any ideas?