About 9 years and 34k miles, bellhousing changed. Mine had no rattle and no vibration but there was movement on the shaft more than tolerance and when it was taken off the bellhousing casing had been wearing away and dropping tiny bits of metal (powdery) inside the case. So, I would always say go by the shaft movement and not necessarily the rattle (as it could be the flywheel rattle you are hearing, which is normal per Nissan).