[ISTA] How do ya know if it is really a SyTy transmission?

[AWD43@aol.com]

During recent wastegate test sessions, I lost 2nd gear.
What are the letter designations on the Syclone & Typhoon 
transmissions that anyone is aware of?  I'm thinking of buying a 
replacement and rebuilding the original while still having a drivable truck.
I have a line on a "supposed" Syclone trans, but want to verify the
 letter codes when I finally see the trans.
TIA,
Mike V.