axle question/problem?

OK, when you split the case of a transmission, and then putting it back together, what would hold the case from going completely together and leaving about about a 1/4 inch gap? it came to me unbolted and split a bit, and I hjave never split a tranny and dont know whats up. I do see a lil snap ring type thing at the end of the case through a threaded hole (it came with no plugs at all either:mad: ) but I dont know if it goes onto the shaft with gears or what?

any help is appreciated.

also there was 2 peices inside the tranny, made of thin sheet metal or something, one is bolted at the baso of one of the large shafts with many gears on it,the other, about 1/2 inch wide, 7 or so inches long, and 1/2 inch dep, it us shaped sorta like a 7 inch long U. it was loose in there and I dont see where it would go, maybe not even to my trans but i dont know, also where the ends of the 2 long shafts go into the case there is a threaded hole that hits each shaft like there would be a set screw there or something.