Subaru Impreza GC8 & RS Forum & Community banner

1 - 6 of 6 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1 (Edited)
hey folks i have a jdm 05 legacy gt wagon with an automatic 5 speed tranny and the first mod i want to do to this is a gearbox please advise me on which box i will need and parts ie: rear diff , axels etc. later on i would also want to convert this to a sti so any help with starting mods needed will be greatly appreciated if it is possible to just drop in an sti power train and would be easier knowledge on this would be appreciated also
tkns for the help my fellow subie lovers,,,,
 

·
Registered
MY98 2.2 Swapped Foz L
Joined
·
281 Posts
I would very highly recommend going with a factory GT 5 speed. You'll need the matching diff, the whole piece of kit is like $3000. Legacy GTs are expensive cars..... but technically speaking, you could throw any Subaru transmission made AFTER '98 in there. Your rear diff is 3.272, and the manual rear diff is 4.11. This means you can get an automatic WRX rear diff to match the GT transmission, but more research is required on that. Usually trannies and diffs are sold as a combo. The GT 5MT is a virtually unbreakable gearbox, with the exception of the 1-2 shift fork (which will bend if you REALLY mess up, but generally it's not that big of a deal).

If it really is a GT, then your engine should be the same at an STI, just with a smaller turbo. (I think. Subaru did this weird thing in '05 where they interchangeably put either the EJ255 or the EJ257 engine in GTs, the 257 was the STI block.) So, bigger turbo, and get a real tune.

As for the possibility of the transmission: I think the ECU is tied in with the TCU, so the ECU will be very unhappy if you just disconnect the TCU.

So, tranny swap parts are as follows: ECU, GT Transmission, matching diff, and all the supporting pieces (manual pedal box, clutch master cyl./slave cyl./lines, a GT clutch, etc.).

Try to look on eBay and Craigslift and Legacy forums for the transmission. Come back here for more help. Good luck.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
05 legacy gearbox conversion

thanks bro this really helped me out im going to start sourcing the parts and i surely will let you know how this goes btw what do y think i can doo about the ecu to keep it happy .......
tkns agen
 

·
Registered
Joined
·
4 Posts
Discussion Starter #4
hey bro quick question how can i tell exactly which engine it is i have im thinking of forging the internals and also i think that my friend has a 6speed mt laying around that hell give me for cheep and eould like to use this for the while will this work
 

·
Registered
MY98 2.2 Swapped Foz L
Joined
·
281 Posts
The 6MT swap will work, you'll just have to fool the ECU into thinking it's an automatic, or get a manual ECU. I'm not an expert on such things, so I'd create a separate forum. As for your engine, go look under your hood at the plate and there will be an engine code there to tell you what your engine actually is.
 

·
Banned
Joined
·
4,438 Posts
JDM spec Legacy and US Spec Legacy are not the same car by any means, particularly the engines. Our Legacy GT Turbo's here are 2.5 liters, JDM are 2.0. I would not take for granted transmissions or final drives are the same either, just as they aren't always shared among other JDM-US Spec Subaru

So it's not enough to say "I have this, my friend has that, can I fit it"

You need to research what equipment your car has (research the VIN with your dealer, get the factory service manual), go off serial numbers for your friends transmission, and that will give you a good basis to start from as far as compatibility.
 
1 - 6 of 6 Posts
Top