This is another way to hold the gears without the correct miller tool. I learned this trick from a friend who has been building transmissions all his life. With the transfer shaft installed use a 3" or so 5/8'' bolt and slide it between the park arm and the metal loop bolted to the case. This will lock the transmission in park which will prevent the gears from turning. I just torqued the nuts using this method and it worked great. He said he has used this method on every 413 he has built, he built a lot of them over the years, and he has never had a problem.

Justin