what trans do i have???

[skidpan]

ok so i have spent today trying to find out what the hell transmission i have in my rig...what i know
its a 1978,
its ALL cast iron,
its shifter is on top,
its attached to a 205 ,
4 speed granny,
its is stamped...
13
GM
486452
on the side of it,
and m20 on the top by the bell housing
now i have looked at every pic i could find of the m20s sm*** and any other 4 speed trans i could find in our trucks.
it looks very simmilar to this, but this is called the clark 5 speed, and mine doesnt have that thing attached to the back. can some one help me out???

 

[sled_dog]

SM465, SM465 and 420 where the transmissions use in our rigs, 420s in the older style ones. I think you messed up when you just typed the numbers on the trans. Should be 484652. At least I think thats what mine says. Here is a picture of one or two of the ones I have laying around. Mine were conected to NP208/241s so they have the bigger adapter.

 

[skidpan]

ohh thank you !!! i dont know why i was having such a problem with it... thanks