1997 Impreza outback rear diff - Subaru Impreza GC8 & RS Forum & Community: RS25.com
 
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1997 Impreza outback rear diff
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Old 09-19-2019, 04:28 PM   #1
t-wrx
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So I just picked up a 1997 Impreza outback with an automatic transmission. It needs some work and I’m trying to breath some new life into it. The rear diff is making a lot of noise and I’m looking for a used one but not having much luck. I’ve been finding conflicting information about differentials that are compatible. I’ve read the final drive for this car is 3.9 on some forums and 4.11 in others so I was hoping someone could chime in on what I should be looking for. I’m sorry in advance if this has been covered somewhere obvious. I know someone will tell me to use the search function and I have I just can’t find a concrete answer. I don’t want to buy the wrong thing.

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Old 09-20-2019, 10:14 AM   #2
wolficus
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I believe the differences in the final drive are from if its a manual or automatic.
Manuals I think have the 3.9 and Autos have the 4.11.

Could be wrong though...
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Old 09-20-2019, 04:07 PM   #3
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Yeah that’s what more sources have said. So I went ahead and ordered a 4.11 rear diff. Should have it by Thursday. I’ll confirm on here that it works.
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Old 09-24-2019, 03:54 PM   #4
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Quote:
Originally Posted by t-wrx View Post
Yeah that’s what more sources have said. So I went ahead and ordered a 4.11 rear diff. Should have it by Thursday. I’ll confirm on here that it works.
Worst case you can just swap the ring gear from your current diff onto the new one, that'll keep your gear ratio the same.
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Old 09-25-2019, 08:08 AM   #5
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Worst case you can just swap the ring gear from your current diff onto the new one, that'll keep your gear ratio the same.[/QUOTE]
I hear you but the ring and pinion are destroyed. The diff had a leak and the last owner drove it till everything completely let go.
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Old 09-25-2019, 08:11 AM   #6
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I got a new diff. It’s a 4.11 out of an 09 legacy. It’s really rusty so I’m trying to find a blasting service to clean it up before I install. It would be the only rusty thing on the car. But once I install it I’ll confirm it works with the 2.2 auto Imprezas
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Old 09-30-2019, 05:09 PM   #7
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Wrong final drive... pretty pissed off. The trans and rear diff are fighting and Is completely undrivable. I guess it’s 3.9 but I really want a solid sourced answer. Can anyone help with this?
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Old 09-30-2019, 06:49 PM   #8
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No one can give you a solid answer without knowing the trans code.
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Old 09-30-2019, 09:07 PM   #9
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Quote:
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No one can give you a solid answer without knowing the trans code.
Trans code is: tz102za5aa-gn
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Old 10-01-2019, 12:32 AM   #10
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Jack the car up and put it in drive. You've got a 4.111 rear diff, correct? If the rear wheels spin faster than the fronts, your trans is a 4.444 FD. If the rear wheels spin slower, the trans should be a 3.90 FD. The higher the final drive, the slower the wheels will spin at a given engine speed, so you should be able to figure out which direction to go. Good luck!
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