madmarx

iTrader: (1)

Is it true that bugeye and blobeye wrx's all have the same diff ratios ? If it is why the need for all the different codes ? unless they are for the gear ratios and not the diff ratio ? eg, TY754VN1AA and TY754VN5AA.

JuergenG

Can't comment on the diff ratios being the same.
But every small change on the gearbox internals results in a new number. These changes don't necessarily have to be ratio changes but can also be changed synchros or even physically wider gears (for more contact surface). Without a new number, nobody could tell, if the gearbox, for example, has the improved synchros of a later version of the gearbox (TY754VV4AA vs TY754VN2BA).
Have a look at the "Notes" column in this chart.

madmarx

iTrader: (1)

Thanks for the info. That chart wont open on my comp. I have this list already - http://spda-online.ca/content.php?44-transmission-chart but it doesnt tell me if i can fit a 02 box on a 04 model etc even though the codes are different.