Supposedly a 93/94 FWD transmission will not interchange with a 92 FWD.    Would like to know why. The only reason I can think is a difference in the CV axles.  From what I have researched, if the transmission is AWD, then the 92/93/94 all interchange.  If AWD transmissions interchange, why not the FWDs?  

CV axles are definitely the same. Only '93-94 FWD MT Imprezas got the 23-spline axles

 

I know there were several gear ratio changes, (not just axle ratio, but 1-4 as well) in those years. And that's all it takes to kick something out of a parts interchange (car-part, etc.) search. I see they list '90-'91 Legacy, '92 Legacy, '93-'94 Legacy, and '93-'95 Impreza as all being different for FWD, non-turbo ATs.

 

 

So I'm not sure exactly, but I bet they'd still work just fine.

i looked this up last night but don't see a reply...weird guess it got lost or i fell asleep...anyway, i looked online subaru parts places.

 

john.c.e says 90-91 have a 4.11 final drive front diff and 92-94 have 3.9: 

http://www.ultimatesubaru.org/forum/topic/119346-transmission-interchange/

 

which doesn't matter for FWD as there's no rear diff to match.  

 

i looked up FWD and AWD 90-93 stuff on subaru online parts sites and didn't see anything to detract me from thinking they wouldn't interchange - although the listings and part numbers are convoluted and hard to make sense of.