The truck: 1986 K5 Blazer 350ci with SM465 3spd manual with granny low transmission NP208c transfer case I was out playing in a field this weekend and threw the driveshaft. I stopped to find out what the awful loud noise was and found the u-joint had apparently freed itself from the straps bolting it to the yoke on the rear differential. Nothing else seemed to be damaged so I threw the driveshaft in the backseat, put the truck in 4hi and drove approximately 200 yards to the house. I put on a new u-joint this evening and then re-installed the driveshaft. I unlocked the front hubs, put the transfer case back into 2wd, cranked it up and started to go. Now there is an awful loud metallic clunking sound and a vibration as I begin to accelerate at a low speed. It doesnt matter whether its in 2 or 4wd, forward or reverse. I even removed the driveshaft and took a lap around the yard with no noise. Anybody have any ideas?