PROPER Filling of '51 Car 3 sp/od

[Shoebox]

So I received my Jug of Sta-lube 90 wt GL-4 and am ready to fill my '51 3spd w/od. The Green Book clearly states to fill (4 1/2 pints) all into the main trans fill hole. There is a substantial size fill plug in the aft portion of the trans,....why?


I recall my dear Dad once recalling how he damaged the trans in his old hunting Ford wagon because he didn't know there were 2 fill holes. Just need to get this done correctly. Thanks.