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Swapping a 1994 Legacy SS 4eat and rear diff into my 1990 NA
Posted: Tue Feb 06, 2007 2:00 am
by voodoochylde
I found an extremely nice gentleman on the forums that may sell me his transmission.
It's a 3.90 4EAT transmission and rear differential. Mine's a 1990 Legacy NA with the 4.11 equivalent.
What would I need to do the swap? Just the tranny/diff? Will my TCU control the newer tranny? Will my axles work?
Thanks in advance!
Posted: Tue Feb 06, 2007 4:34 am
by 555BCTurbo
I think you might need the Turbo TCU...
If so I have one that I could hook you up with for cheap
Posted: Tue Feb 06, 2007 6:51 pm
by Legacy777
You'll probably be fine with your existing TCU.
Is the tranny from a turbo or non-turbo legacy?
Posted: Tue Feb 06, 2007 10:42 pm
by voodoochylde
555BCTurbo, nice name and thanks for the offer. I'll keep ya in mind.
Legacy777, it's from a turbo legacy. Since I'll have relative ease locating a TCU, I'm more worried about the axles/stubs. Am I correct thinking the only different axles in this year range (1990 - 1995) were between LSD and non-LSD?
Posted: Wed Feb 07, 2007 2:47 am
by AWD_addict
I know that a NA 4.111 4EAT will work normally with a TCU from a TW's 3.90 4EAT.
You're probably correct about the axles.
Posted: Wed Feb 07, 2007 4:01 am
by voodoochylde
AWD_addict wrote:I know that a NA 4.111 4EAT will work normally with a TCU from a TW's 3.90 4EAT.
You're probably correct about the axles.
Meaning...the turbo wagon's TCU has enough brainpower to control another 4eat...hopefully that means my NA's TCU is as smart
Thanks for the input
Posted: Fri Feb 09, 2007 7:09 pm
by Legacy777
The axles are the same, so you shouldn't have a problem.
Posted: Thu Jul 05, 2007 7:02 pm
by wtdash
voodoochylde
I'm doing a similar swap, except I'm replacing my '90 w/a 4EAT and LSD rear diff from a '91.
Did your swap go as planned?
I'm looking for any/all info that my Haynes manual may leave out.
Thanks!
Posted: Mon Jul 09, 2007 1:26 am
by AWD_addict
voodoochylde wrote:
Meaning...the turbo wagon's TCU has enough brainpower to control another 4eat...hopefully that means my NA's TCU is as smart
Thanks for the input
Sure. If it can't do it, I have a turbo TCU for sale.
Posted: Wed Jul 11, 2007 8:33 pm
by Coy
so that means that if i got a rear section of a driveshaft from a 90 n/a 5 speed it would fit into my 92 n/a 5 speed, no fuss no muss.
i hope cause its the only option ive found to get my problems taken care of.
Posted: Wed Jul 11, 2007 10:39 pm
by wtdash
Coy wrote:so that means that if i got a rear section of a driveshaft from a 90 n/a 5 speed it would fit into my 92 n/a 5 speed, no fuss no muss.
i hope cause its the only option ive found to get my problems taken care of.
If the driveshaft includes the rear diff see below:
I believe the '90-'91 are 4.11 rear dif ratio for non-turbo; '92-'94 are 3.90.
I KNOW they are for the Automatic. Double-check on the 5spd.
EDIT 7/17/07:
This link has good info on rear diffs and AT vs. MT for '90-'94 models:
http://legacycentral.org/library/transmission/intro.htm
Posted: Sat Jul 14, 2007 7:12 pm
by Coy
my 92 has 4.11
see here that way im not hijackin this guys thread.