My 1997 Z28 has a loud vibration noise (a low pitched DDDDDDDDDD that you can feel) that seems like it may be the drive shaft when I get up to 90 mph or so. It also occasionally does it at lower speeds but with a higher rpm. Do I need to replace the driveshaft or can this one be balanced, does this sound like it's the problem even? Also , my father in law has a 1992 RS and needs a hatch motor assembly most of the assemblies that I have found are much larger than the one he has, are they interchangeable? Thanks for your time, looking forward to your response.