Reis Taylor

I blew up my rear differential, pulled the axles and the differential all out as one unit. I had forgotten to do any form of a reference mark in regards to the propeller shaft so when I replace the rear differential axles and all as well as pulling out the propeller shaft I had no way of referencing the propeller shaft to the new rear differential that I installed. And so I have no idea on how to align it back up again. What can I do to align it properly?