In my diagnostic search I removed the shocks. There is oil canning in the bed side panel passenger side. I experimented by wedging a 2x4 against 2 pieces of plywood in the bed to hold it stiff and I still got the noise.
I am now down to the e-brake cross shaft. It is loose in the mounts and I had wedged wood between it and the cross member to keep it tight. However where the curved part goes near the cross member it is very close. Also there is a groove worn in the cross shaft where the half round crescent shaped bracket (on the cross member)is riveted.
I am now in the process of removing the e-brake cables from the cross shaft so I can rotate the shaft away from the cross member, lock it in place and test drive. The clevis pins however are rusted although they rotate okay they are frozen in place. I spent a long time cutting one off last night with a power saw and this morning I picked up a portable acetylene torch to try and free the other. I am working almost below the gas tank (in the cab) so if I don't give you an update you will know what happened!
