I did one last winter, (1973 T140 Bonneville) and took the transmission apart to inspect, replace seals when I split the case for the crank removal. The phasing of the shifter isn't bad, followed the book for a while, but the Clymer only gave procedure for the 4-speed. I just figured it out for the five speed. Pretty sure there is a bolt in behind the "inner" transmission cover, IIRC
Too much is just barely enough.....