Hmmm, that is weird. I found it using a GM parts lookup. Item 431 is the part your talking about and NOW I remember it. You may end up finding pieces of 432 in the bottom of the pan. They have a tendency to break.
And I just found it in the ATSG manual.
Page 71, figure 134. It takes a special tool to R/R the bearings shown as 431. From the looks of it, maybe just a good size socket would do just fine. But either way, your not replacing this with the trans installed in the car. Its coming out. At least part way so you can remove the side cover, the pump covers and the case cover assembly.