Well I got answer from JC, and he gave some things to try out.
I took the woofer and amp out, and they both seems to be in good shape. I suspect that it might was the cable running to the woofer that was vibrating against the plastic cover inside the amp cabinet.
I tried to alter its location a bit and it helped. Its still some vibrations if you crank up the volume but its much better. I will try to find something to put in between or around the cable that can stop it from vibrating just to make sure. Im not certain though about how hot it gets in there, and dont want whatever I use to start melting.
