C4 transmission filter?

Hey guys, got a quick tech question. I'm planning on doing a transmission filter/pan gasket on my 66 mustang with what i thought was a c4 transmission, but i got stuck and wasn't paying attention. I removed the drain pan, no prob, looked at the filter closely and thought it was the same, but there is a small difference. the filter thats on it has a little edge that pokes out away from it that retains a pin and spring in the valve body. problem is it fell out while i wasn't looking and i'm not positive of how it goes back? anybody with any idea of what kind of transmission this is or how it goes back in. the c4 automatic gasket is exactly the same, as is the filter for the exception of the little edge that comes out of the original holding that pin and spring. if anyone can give any advice it's greatly appreciated. tried looking at the spring and pin to see if there were wear marks on it to maybe put it back in place, but i'd rather do it right the first time! stumped

that and about how much tranny fluid to fill her back up?

picture

thanks for the posts... its definitely the 2nd one down on the left.

as you can see that little lead towards the bottom comes out. i'm not positive but i believe the pin fell out from behind this. but like i said not sure.

keep me posted

so just to make sure, this pin and spring go into the valvebody right where the notch on the filter into the valve body right? so what direction do they go in.. the pin is an upside down T shape and the spring is like one in an inkpen... so does the pin go in upside down with the spring up top or down below and on the pin? maybe a diagram would help rather than a description ha.. i'm not brain dead. just wanna get it right