where is 3 speed manual trans drain plug?

[hplacecf]

hi.

newbie here.

trying to find the drain plug for a 3 speed manual trans.

just bought a
1977
c10
250 engine
3 speed manual trans.

I am changing out all of the fluids and belts and hoses. so far, so good.

I am at the point where I want to change the manual trans fluid.

I found the fill plug (man, is it on tight, but that is another story...), but I can't find the drain plug.

I searched the net, this forum, the Haynes and Chilton books, and can't find a pic of the drain plug.

I see other bolts that look like they hold the trans together, but no drain plug - at least no OBVIOUS drain plug.

does anyone know where it is and/or have a pic to share?

many thanks!