These noises are tough. Ride in the bed and see if you hear which area it is from, front or back, left or right. Hang your head out of each window. Be sure it's not wheel bearings in back or front. Check those both for high heat when done driving.(feel inside and outside of the wheel) If you start to go crazy, get someone to pull you in a quiet area with a long rope so you don't hear the tow vehicle. This is done with the driveshaft(s) removed. At least you will forever eliminate all that then start eliminating other parts. BUT if you have sandblasted near a rear end, it's curtains!! To all others: DO NOT sandblast rear ends, transmissions and such unless you are going to rebuild and don't buy one from some guy who just sandblasted one of these items to get it clean for paint. This warning is in all restoration books I have read.
