Newer (5EAT or CVT) auto trans in 91 SS?

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IronMonkeyL255
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Newer (5EAT or CVT) auto trans in 91 SS?

Post by IronMonkeyL255 »

Is it possible to swap a newer 5 spd or CVT auto trans into a '91 SS?

I was involved in a motorcycle accident in late 2017 and lost the use of my left arm (and later had it amputated), so I can no longer hold the wheel and shift at the same time. I can drive an automatic with a spinner knob on the wheel, and luckily I opted for the CVT in my 2014 Impreza daily driver. Unfortunately I swapped my '91 SS auto to a 5 speed from an '06 WRX in 2007 so I can't drive it until I swap it back, but I sold all of the auto trans bits already (I think I may still have the TCU, but nothing else).

If I am having to go to all the trouble of swapping again I would prefer to put something better than another SS 4EAT, but I have been told that there is a potential problem with the immobilizer from the donor car. If I need to go with another 4EAT I would prefer to have one of the rear biased VTD units if such a thing exists (and maybe get it built).

I used to be more active here, but got swamped in work, and then the 2 wheel bug bit me until my accident (not my fault - car pulled out of a driveway into my right of way). Hopefully someone has some information that can help me out. I contacted Dale Teague at Boxer4Racing and he said he may be able to get his hands on a donor SS for most of the parts for a straight swap back, but I can't help but think there is another way that I am missing.
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
IronMonkeyL255
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Re: Newer (5EAT or CVT) auto trans in 91 SS?

Post by IronMonkeyL255 »

Or if anyone knows of a way to electronically/hydraulically/pneumatically shift a manual transmission.

Times like these, I really wish Subaru had a dual clutch tranny in their offerings.
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
Legacy777
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Re: Newer (5EAT or CVT) auto trans in 91 SS?

Post by Legacy777 »

I'm sorry to hear about the accident and your arm, but glad that you're still here and have an enthusiasm for cars :)

Regarding the AT...the biggest challenge you will run into is the electronics and the various sensors needed by the AT computer. You or someone would need to look through the various wiring diagrams and determine what sensors are needed and add those so the new AT computer is happy. The immobilizer may be able to be taken care of by a reprogramming from the Subaru dealership.

I actually have been talking with a guy in California that is wanting to swap a 5spd into his I think 06 Forester XT. We have been talking over the past few weeks/months. One of the discussion points was around swapping the ECU and the immobilizer. If he were to use a different ECU I think he said he would need to go to the Subaru dealership to have it reprogrammed.

I don't want to say what you want to do is no possible, but it will likely require a bit more research, time, and money vs. just sticking with a 4EAT. You may want to reach out to the guys at https://www.iwireservices.com They specialize in plug & play and harness merging. Maybe they have some more info for you or at the very least could maybe work with you to make a harness if you figure out all the pieces to make it work.

Regarding the rear biased VTD transmissions, I think that would be an easier swap and can probably be found in early-to-mid 2000's WRX's and other turbo subies. There would likely be additional wiring and/or harness work to make it work, but I think that could be easier...maybe...maybe it's the same effort as a 5EAT or CVT. Any of the newer transmissions would require modification since they use an 8-bolt setup vs. our 4-bolt. Below is from my 6spd swap details thread. Check out the link to the starter modification. You would need to do this or something to this effect.
Legacy777 wrote:Starter – 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.
Have you tried talking with Cobb or any of the other "bigger" Subaru shops to see if they've done 5EAT/CVT swaps to older cars? It may be a long shot, but probably couldn't hurt to ask.

Feel free to bounce stuff off me...I like the troubleshooting/challenge :)
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
wtdash
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Re: Newer (5EAT or CVT) auto trans in 91 SS?

Post by wtdash »

HI,
Kind of a tangent, but FWIW, you CAN swap in any 4EAT from '90-'98, based on what I've read and your original TCU/TCM will run it - and it'll plug-in on the bellhousing harness (still might want the TCU w/the Trans).

If you didn't know, the '95-'98 2.2 were 4.11 FD ratio; '96-'98 were 4.44 (OB, GT, LSI, RS, Foz) The GT and RS would be closest for gearing and speedo calibration due to their 'shorter' tires.

I 'think' that '06 WRX is a 3.7 FD Ratio (kinda oddball) as I was considering one for my '98 Foz project.

Your SS would have been 3.9, so you'll need to get a matching diff regardless.

And remember that rear diff flange - it changed in '95ish. So whatever you get, ensure it'll match your driveline or vice versa.

And glad you're still 'in the game'. I mostly gave up street bikes for that same concern - even though I was a defensive rider, being 'hyper-vigilant' kinda got old.
Turbo Subies:
'87 GL-10 Turbo - SOLD
'90 BJ EJ22T/DOHC & 5speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX -SOLD
'96 BD-turbo'd-SOLD
'98 SF - NA-T
IronMonkeyL255
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Re: Newer (5EAT or CVT) auto trans in 91 SS?

Post by IronMonkeyL255 »

wtdash wrote: Wed Dec 09, 2020 7:23 pm HI,
Kind of a tangent, but FWIW, you CAN swap in any 4EAT from '90-'98, based on what I've read and your original TCU/TCM will run it - and it'll plug-in on the bellhousing harness (still might want the TCU w/the Trans).

If you didn't know, the '95-'98 2.2 were 4.11 FD ratio; '96-'98 were 4.44 (OB, GT, LSI, RS, Foz) The GT and RS would be closest for gearing and speedo calibration due to their 'shorter' tires.

I 'think' that '06 WRX is a 3.7 FD Ratio (kinda oddball) as I was considering one for my '98 Foz project.

Your SS would have been 3.9, so you'll need to get a matching diff regardless.

And remember that rear diff flange - it changed in '95ish. So whatever you get, ensure it'll match your driveline or vice versa.

And glad you're still 'in the game'. I mostly gave up street bikes for that same concern - even though I was a defensive rider, being 'hyper-vigilant' kinda got old.
I might have to look into a GT or RS tranny/diff, but I think I am going to need to get a donor Legacy SS since I am missing so many of the other parts that I would need. Once I do that, I might look into other things (I was already considering a build from IPT or Level 10).

I had to deal with all of the FD ratio stuff when I was swapping to a manual, and was lucky enough to snag an '06 WRX tranny with matching diff in '07 from a guy that was probably swapping in an STI 6 speed. From what I have seen, the '06 WRX Automatic is 3.9 while the manual is 3.7, which is annoying since I don't think any automatics needed a 3.7 rear diff (so I can't keep the one I have,,, :( ).

I remember having to swap the flange, and will opt for the flange puller instead of the hammer I used last time.

I was a hyper vigilant rider, which makes me (and the friends I rode with) wonder what happened that day. Not knowing is the second worse part of this after losing the arm, since I don't know if/how I messed up. The best I can figure is that she stopped and looked like she wouldn't try to kill me, then did anyway. I never even got a chance to talk to the cops about it since by the time I came out of my coma and felt I was ready, the trooper who had my case didn't work there anymore and the supervisor said that he was the only one who knew anything more than was on the accident report.

Drivers have been getting worse and worse lately (probably distracted by phones), and I wish I had realized it before it hit me in the form of a Nissan Altima.
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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