2004 outback awd drivetrain fit a 1991 legacy awd??

Flywheel, Clutch, Transmission, Axles, etc...

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Garbels90
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2004 outback awd drivetrain fit a 1991 legacy awd??

Post by Garbels90 »

I have a 1991 legacy awd that im looking to put a drivetrain into. I have a 2004 outback with very little kms so i wanted to use the manual transmission, prop shaft and rear diff amd just swap all its guts over to the legacy.
Now i know the wheelbase is longer in the outback but i have a shorter prop shaft that "should" fit.
Has anyone done this before??
Anything i should know beforehand?
Legacy777
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Re: 2004 outback awd drivetrain fit a 1991 legacy awd??

Post by Legacy777 »

I don't see a reason why this wouldn't work as long as you match up the correct length prop shaft.

How much of the drivetrain are you looking to use, manual transmission, prop shaft, rear diff?

The transmission mating to the engine is going to be different. Since the newer motors have an 8-bolt setup vs. the older 4-bolt setup, you'll need to do something for the lower starter mount hole. The best option is to use an M14x1.5 bolt aprox 40-45 mm long. You'll need to tap the lower bolt hole on the trans and drill out the lower bolt hole on the starter to 9/16". More info can be found in this thread.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

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IronMonkeyL255
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Re: 2004 outback awd drivetrain fit a 1991 legacy awd??

Post by IronMonkeyL255 »

When I swapped my '91 and put an '06 WRX 5 spd tranny and diff in (and it looks like the Outback has the same setup as that WRX), I was able to reuse the '91 Legacy manual prop shaft (I had it remanufactured, though) once I changed out the flange on the input of the rear diff.

I had to use the '91 CV joints because the WRX ones were way too long to work, but the '91 had a stub on the diff/tranny side while the WRX joints socketed in with spring retainer clips to hold them in place. I solved this by using axle stubs and diff/tranny seals from the '04 STI (not '05-'07, since they went to 5x114 wheels and changed a bunch of other things). I included a list of the part numbers below and it is the same for tranny and diff, just double the quantities. Make sure to put the seals on the correct sides, as it will likely leak (just weeping, not a fast leak) if they are on the wrong sides. I found this out because the wingnut behind the parts counter gave me 2 RH seals (the LH was in the wrong bag, and I didn't think to double check the part # on the seal).

806730042 Oil Seal LH x1
806730041 Oil Seal RH x1
38415AA110 Axle Stub x2
805329010 C-Clip x2

IIRC I just tapped the starter mount and used a spare turbo stud that I had, but don't quote me since I did it over a decade ago (2007). Don't worry, though, I double checked the part numbers above before submitting this reply.

Hopefully this helps.
Disclaimer: If anything I post is inaccurate, please correct me. I do not wish to add to the misinformation floating around on the internet.

That being said, everything I post is accurate to the best of my knowledge.

Rio Red '91 Legacy SS
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