I need a bit of input here, got a 97 K2500, 350, auto and 14 bolt (we think) posi, 3.73 gears. Assuming it's posi because it seems to want to spin both rears under plowing loads. It started developing a noise in the rear a couple days ago. Sounds like a metallic buzzing, very much like when the t-case doesn't engage fully and the gears are just touching. Doesn't seem to be related to power input, it sounds off under low throttle as well as hard acceleration. It doesn't seem to do it at speeds over 20 or so. I'm thinking that it's a posi clutch acting up, could I be right? Also, does anyone know the build code for posi? Any fix that can be done in God's Garage (outdoors)? Not running the truck at the moment, want to get it fixed before it can do any further damamge, I'm going looking for a shop appointment tomorrow morning.