[Mike_The_Grad]

Hey everyone, this issue is on my 72 c10 lwb with leaf spring suspension. Brakes are brand new(last weekend) all the way around. Yukon gear posi with richmond 3.08 ring and pinion and timken bearings all installed last year. Th350 rebuilt last year with shift kit and stock torque converter. Factory steel wheels 5 lug. Swaybars front and back. Caltracs traction bars. Timken center support bearing (last year). Spicer life series non greasable u joints. Slip yoke greased recently. Kyb gasajust shocks 2 years old

Hopefully that helps with the questions regarding what I'm running. Now to the issue. When I'm driving down the road, doesnt matter how fast, time of day, loaded/unloaded, turning or not, if I hit successive bumps in the road I get a loud metal on metal grinding sound. But only if I keep accelerating. If I let off the gas it goes away. I dont even have to hit the brakes because ad soon as I let off the gas pedal the sound stops and does not return unless I hit a bump in the road a certain way. At first I thought it was wheel bearings or brakes. Well I've replaced the front wheel bearings and have them properly adjusted. Then I thought it was a brake pad backing plate loose and dragging on the rotor. I replaced/overhauled the rear drum brakes and the front disc brakes. Now it stops great and have no squealing or chatter. I tightened up my exhaust connections and now the truck sounds and brakes awesome. One time as I was experiencing the noise I kept my foot into the pedal only enough to maintain the noise and I shifted into neutral, the noise did not change and was still there. I let off the gas the noise went away. Shifted back into drive and noise did not come back. There are certain parts of the road around town that I know will cause the noise on my truck. If I coast through these areas the noise does not happen. If I am accelerating through these same areas i get the noise. Let off the gas, noise goes away. Lastnight late at night driving home and the only vehicle on the rural road. I heard this noise, so I leaned over to the passengerside with the window down and the noise was less noticeable. So I put my head down towards the floor didnt hear anything. Stuck my head out of the drivers side window, could hear the noise louder. It sounded like it is coming from the rear of the truck. Possibly the rear drivers side drum brake. Or something in the rearend. I just had the rear drums apart last weekend. I replaced the shoes (installed them correctly) installed brand new spring kit. Greased the backing plate where the shoes ride. Wheel cylinders are raybestos and were replaced a couple of years ago. The drums showed no scoring. The drums and brake assembly are dry. I dont feel like its dragging. Truck stops just fine and in a straight line. No skidding. Brake fluid level is where it's supposed to be. Master cylinder is about 3 years old. No broken springs or debris inside drums when I pulled them. Didnt appear out of round. No dragging when I adjusted them. Self adjusters are new and parking brake is adjusted and works perfectly fine. I'm stumped!!