Originally Posted by GDR
Just taking a wild guess by looking at assembly drawings. One of the retaining bolts came loose from the rear bearing and got shot or forced into the case by the transfer gear.Take a look in that hole and see if that's where the gear is.
So I took a look inside and I can see the gear. I'm pretty sure you were right. I'm guessing it's one of the two bolts I circled in the pic below.
I don't have any experience opening up a tranny but I did do my own tranny swap so I'm not mechanically challenged. If this is the problem, would repairing it be as easy as pulling the rear of the transmission off then replacing the bolt and having it welded?