I never have done anything to the rear end on the camaro aside from change the fluid, put axle seals in it, and tried to put a drop in posi in it. It is a weird first year 8.2/8.5 so the lunch box posi wouldn't fit. I've always planned to rebuild the rear end and see if it was the vibration. I'm guessing no. I should have the drive shaft balance checked too but ya know, that's hard to do when it's your daily.