Sometimes when I start from a dead stop and I am letting out the clutch I get sort of a moaning sound. Like when large truck steps on the brakes. Also I am not on the brake pedal at all when this happens. I started about 2 weeks ago when I noticed it. It seems to happen more often when I let the clutch out slowly. Does any one have any idea what it could be? I don't think it is a normal sound.