Cluster gear shaft- drive out forwards or backwards?

[johnbuckley]

Les Andrews book p 1-336 says "the cluster gear shaft is slightly larger diameter ( 0.001 ") at the front end and should only be removed through the front of the transmission case. Forcing the shaft out the rear may crack the case" , but a couple of the Youtube clips of transmission rebuilding rebuilding show the shaft being driven out backwards. Did the spec of both the the cluster shaft and the case change when rubber O rings were fitted?