Hard to tell exactly where noises come from even while laying down in the back. Tightened lift gate by moving latch a bit. No luck. It stopped a big rattle a couple of months ago. Thought it had moved and loosened up again. Looked at Jack. Somebody had mentioned that on here. Seemed very tight. Thought it was pointless but WTH. Doubled up a old sock and smashed it in between the jack and the plastic wall of the interior. Bingo. No more banging noise when going over bumps. Cool. Now if I can find the gieger counter noise under drivers dash. Hard place to get into. Still trying though. Hope this helps somebody. 2015 Yukon 38,000 miles. Never would have bought this car if I had known all the problems I would have in the first year of ownership. Put 6500 miles in one year of owning.