Hi Franklin,
I have this same smell. I took off the back too, and the only thing I can guess it might be is a square piece of rubbery material that is glued to the top of the compressor. I am assuming it is sound deadening, but with the heat of the compressor it off-gases. I just bought my fridge (LG's GR-389RT), and it is working great in every other way. But that smell! I think it might void the warranty to pull that black patch off, and it might be louder too. Also, I'm just plain afraid to wreck something. Any comments?
Joe