833 OD vibration

Drive shafts have a working RPM range. They are balanced with that RPM range considered. Every drive shaft will produce a harmonic vibration or drone if it is spun out of its balance range. This is why I asked about the overdrive situation. You must multiply the RPM of "high gear" third, times .73 I think it is for the over drive. This may well give you an RPM that is out of the range of balance for a normal non OD drive shaft.