i've had two hatches that wouldn't lockall the way, so when i hit a bump they would bounce open and close. it made a pretty loud bang.

if that's the case. i just would slam the hatch down real hard, so it locks. its not really fixing the problem, but hey i don't have a delicate touch.

in addition. rex's make creaking noises, sometimes loud popping while cornering hard or even on rough roads. its just the body twisting.