Strange grinding and rattling noise coming from retina macbook pro 15 inch bought in september 2012. Just noticed the sound today as it was stationary on my desk, pick it up to notice moving the laptop in upward/downward motions recreates the sound as if something large is moving around. My main concern is. if the problem is unfixable and merits a replacement, will i receive the 2012 model (as i desire), or will i get the latest model that only has integrated graphics and fragile glass display... any insight appreciated or if anyone else has had a similar grinding noise. Seems to get louder depending on the laptops heat.