This has broadened my knowledge in this section. Thanks for sharing...🚗🚙

 

Almost every video I've viewed on youtube does not mention the 17mm fill bolt that op is referencing. I have yet to double check the FSM for accuracy.

Edit : the fill sits lower than the drain. How would you top it off if it leaks back out?

 

A couple do as well as one write-up I came across. The confusion suggested I should confirm with the FSM--which I did (see above). It seems the Celica guys figured this out long ago: For those changing the transmission gear oil(C60 aka 6...

EDIT: the picture I included above is misleading; the actual fill hole isn't as low as it appears there. I don't know the internals or design of the two cases, but I can tell you that after filling the 10mm allen bolt drain hole, I got what seemed to me at least 500ml into the proper fill hole (could have been +/-). The Celica discussion I linked suggests that filling both could lead to overfilling. I would assume the 10mm is not meant as a frequent service bolt: it has sealant applied from the factory (as per FSM) and it's an odd fastener. It might be a service point during rebuild. Of course, I'm not a Toyota trained tech or transmission expert, so I can't say. But it would appear the proper method of changing the oil is to drain from the lower 24mm and fill in the 17mm.