10 bolt CARNAGE

so u know those bolts that are sideways that go into the ring gear, well one threaded itselve all the way out and ripped a hole in the cover, and then theres like 3 or 4 bigger bolts inside of the ring gear one came out and looks like a rock ha it caught it selve somehwere where it cant do anymore damage so im just gonna get a new cover and torque down every bolt but why would this happen if i never touched the rear end just chjanged oil


