In 1985 I special ordered a 1 ton 4x4 just the way I wanted it. Not a dually, 454, 4-56 gears, all the bells and whistles. It was a great truck except it had the "factory clunk" from day one. When putting it in gear, brake pedal pressed, it made a loud metallic "clunk" like the u-joints were gone but it wasn't them. I took it to our two local dealers, both said tough luck, it's a normal condition, nothing was wrong. I complained up the chain of command but no luck. I sold the truck a few years later. Fast forward to now. Last year I bought a creampuff 1990 suburban 1500 4x4, 5.7 with only 30,000 original miles and it has the same noise. I have since heard that packing grease somewhere in the driveline would fix it for a while, is this true and how and where do I do it ?? Also, is there a permenant fix for this ? Thanks in advance.