Normally, we strongly recommend that you follow the manufacturer's instructions when installing any aftermarket piece. In this case, our man Harrigan had a pretty cool variation that we think worked pretty well. He started by assembling the unit on the bench. This is the ring gear-side coupler (left) and driver. Note that the spacer paddle (arrow) was properly inserted into the driver, and the paddle opening in the synchro ring was positioned so the two pieces could be properly mated.