Legacy 4WD Tranny Question

[rolerick]

Are there any 5 speed 4WD trannies that will go into a 1990 legacy without too much difficulty? I did a lot of searching around, and didn't find a whole lot about legacies. I'm wondering how difficult it would be to make my FWD manual leggie into a 4WD.

Edited February 18, 2009 by rolerick

[what huh]

A new transmission will be required. Along with the new transmission comes the front diff, center diff, and tailshaft. You must also get the corresponding driveline for the transmission (side note here, if you are merely swapping one AWD transmission for another the MT typically shares one driveline between all other MTs and the ATs share another driveline; the STi 6-speed uses an AT driveline). There are many rear diff options, and any of them can be used as long as the final drive matches the final drive of the rear diff of the donor car the transmission came from. Front axles should be interchangeable, but newer axles are thicker. CV strength has remained the same and are not a weak point. Rear open diffs can be found on most Subaru models. Rear LSD s came on some Legacy Turbos, Some SVXs, 2000-2001 2.5RSs, and 2002+ WRXs. While final drive ratios vary, the axle splines do not. Your diff choice governs which rear axles are to be used. You will either need rear axles from an open diff Legacy or GC/GF/GM Impreza for an open diff or rear LSD axles from a 2000-2001 Impreza 2.5RS (ask for axles from 05/2000+ to be safe) for a rear LSD. If you are converting from AT to MT or viceversa, you will need the corresponding ECU since the AT ECU expects a TCU signal. You can trick it as some have done.

 

Along with the basic driveline components, you are going to need most of the rear suspension and mounts from the transmission back. This includes the transmission crossmember, rear diff crossmember (and all in between), AWD gastank with driveline hump, struts and springs, AWD knuckles, a plethora of bushings, with the possibility of lateral links, swaybar, and trailing arms also being needed. Your best bet is to find an entire donor car that can be stripped. If that is not an option, you will be, as beachbum has said, 'nickle-and-dimed to death'.

[rolerick]

Hey, I really appreciate the info. Sounds like it would be a heck of a project.

[what huh]

yeah it would be fun but, well not really fun at all

[The Scooby]

ive done the swap on a few cars now, takes UNDER 4 hours if you have a car hoist.

 

that includes swapping the tranny, clutch, and flywheel. droping out the old rear suspension cradle as a whole, and putting the new one in. then toss in the drive shaft and your done.

[what huh]

if you do it this way, you would want to get a parts car. what i said before is just list of things you need.

 

And if you shop around for a parts car you could probably find one very very cheap ($800) one that doesnt have an engine or has been rolled or, im sure you get the picture. Even a whole running one for cheap ($1500) you wouldnt have to do the swap. Just sell the one you have and buy the AWD one

[rolerick]

What is the swappability (new word?) when it comes to transmissions? Would I have to use a specific one?

[The Scooby]

any EJ AWD tranny will work.