I did add fluid to the rear. I got conflicting information on exactly how much to put in, I think the service manual said 8oz and a few places online said fill through the speedo hole until it runs out. It was a pain to get fluid in with the floor access riveted shut but I figure I put a good 10-12 oz in before I gave up on waiting for anything to run out. I didn't tear into the trans, only replaced gaskets.
