Originally Posted by R Leo

You need to check the FSM to confirm but, I believe that in post-1983 production, the cast-in witness marks on the driveshaft halves were used during assembly at the factory. If that's the case, you should be able to inspect the driveshaft 'in situ' for proper phasing/orientation and, if the FSM supports my memory, you could reassemble it correctly according to the marks. Prior to some point in '84 the marks were on the shaft halves but weren't used at the inital assembly.