I have a Super T-10 4 speed. Everyone refers to an "S" code or a "W" code ... but where is this letter located on the case. I have about 4 different locations on my transmission stamped with a bunch of random numbers.

 

Are you serious ... zero people know where to find the ID code

 

I have seen it on both the top and also the left side maybe in another place also, mine is on the left cover so I thought that would be where all of them were but than I found out that the T-10's case was changed, so there are aluminum cases and cast with an aluminum tailshaft housing from what I understand the cast with the aluminum tail housing was the older model witch is what I have but hey I cant complain I got mine for hanging some doors on a 78 camaro

you can call jegs @ 1-800-345-4545 they will be able to tell ya for sure!