New found opening in my gear box

I hope everyone is healthy and heading the warnings. I was just under my e type I was going to change the engine oil and trans. Looking at my trans it looks like I’m missing a cap of some sort. It’s on the first part of the gearbox and the hole is threaded. I’ve found my regular drain plug but I don’r know what went in this threaded opening. It’s about an inch in diameter. I cant find a photo of the underside of the gear box. Any ideas?
Many Thanks / Jack

My S2 has a pair of holes in the bellhousing. One is right under the flywheel (you can see the engine number when the flywheel comes around) that has a rotating cap/plate covering it. The other is open (I cover it with a length of Gorilla Tape) and under the throw our bearing. I use it to inspect for wear on the TOB.

Hello Jack,
It would help a lot if you were to describe the position of the Threaded Hole; “on the first part of the gearbox” is fairly broad. Are you referring to an additional opening to the Drain and the Filler Hole, or are you confusing the Filler Hole as the mystery opening?

The following picture shows the Filler Hole.

Regards,

Bill

Well if it’s on the transmission and not the bell housing it could only be the hole for fill plug

Thanks everybody. This site is great. It is in on the bell housing.I guess I’m missing the cap for it. Don’t see a part number for it. Goriila tape on the other. Man I was thinking was this hole holding some oil back?
Many Thanks again.

IIRC, that is for removing the clutch fork pivot shaft.