.

 

im in the same boat dont know what year my tranny is to buy a clutch for it. what you look for is the first lettering would say S1 meaning a LS tranny and GSR is YS1

 

no, it has been my understanding that you would have to crack it open and count the teeth on the actual gears.
http://www.bseries.net/html/specs/btrannyspecs.php

i cant seem to find the ffsquads b gears page but this one shall do.

 

Really? H series trannies have the codes right on top...pretty easy to under stand...M2F4, M2B4, M2S4, M2L5 etc....

 

I am not sure if they have the same codes or not...worth some research though.
You just have to rely on the owner of the tranny telling you the truth. When I got my tranny, I travled 460 miles one way to pick it up. I asked the guy over the phone several times, "You sure that it came out of a GSR?" Sure enough when I got it home and cracked it open...it was a GSR. At that point though I would have settled for an LS tranny.

 

If it were me, I would trust him. However, I am probably too trusting.
I payed *cough cough* $100 *cough cough*, and that also why I was willing to take the risk. However, I had to put new 1,2,3 and R synchros and new 2 and 3 gears so that brought the investment way up.