No clue what this rattling noise is. Faster rotations as I accelerate. Thoughts?? Mechanic is stumped and can’t recreate the noise whenever I bring it in.

files are too large to upload so here are Drop Box Links to the videos (don’t mind the commentary):

https://www.dropbox.com/s/2s0dhpjppp8ccnv/Lr3.MOV?dl=0

https://www.dropbox.com/s/yx4wafu74uw2r2z/LR.MOV?dl=0

https://www.dropbox.com/s/ad82vjghltwo8l0/LR2.MOV?dl=0

 

Have you checked the water pump? I had a similar type of sound/rattle that turned out to be the water pump pulley/shaft slowly wearing out before it gave it suddenly.