Was hit when I was fully stopped during a stop and go traffic flow. Yukon had 100mi on it and only was 10days old
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Ouch.
To be honest, I can’t see much damage from your photo. The other guy definitely got the worse end of the deal.
Looking at the various lines on the liftgate and the corresponding lines on the corners, it doesn’t appear to my untrained eye that anything is really out of alignment. At least not enough, in my opinion, to cause the interior trim pieces to break, but I could be wrong. The various photos of the interior trim pieces appear to me to show factory edges on the pieces and not cracks. It may have popped some mounting tabs on the backside to cause the piece to be able to flex a little.
Have you had an insurance adjuster or body shop look at it yet?