so ive posted that i have grinding noise, usually cruising or light throttle under mph, i always thought it was a bad solenoid and my hubs grinding, but the problem still exists in 4hi and 4lo, so what could this be? i would say it sounds like a piece of metal vibrating and grinding say the brake shield? but i have pulled those off and the sound stayed the same. what could this be now? a bad cat? or what?