I have an 04 Silverado with 200,000 miles on it. When I accelerate, it sounds like chains are being thrashed and rattled around. Any idea what this could be? I took it to the shop and they said the U joint looked fine and transmission looked good. Don't know why they couldn't find the issue. The sound only occurs when the wheels are turning, not when the engine is revved in neutral. Truck drives fine, just a horrible noise. TIA