For RM350 hydraulic power packs:
The (discontinued) splined shaft pump part no is 16534
The (discontinued) motor adaptor with coupling and bolts for splined shaft pump is 16535
The motor coupling only for the splined shaft is 17020
The (new) taper shaft pump part no is 17017
The (new) motor adaptor with coupling and bolts for the taper shaft motor is 17019
If you change from a splined shaft pump to a taper shaft pump, you can't just change the pump and motor coupling, as the shaft lengths are different. You have to change the adaptor with coupling and bolts complete.