Rear axle question

[brentlysubaru]

Got a 97 impreza obs. The rear diff is going out and figured put in an LSD when I change it. I was wondering about the rear CV axles. Are they different than what is in the car? Do I need to change them when I change the rear diff? The rear diff I'm getting is out of a 02 legacy GT 5spd

[1 Lucky Texan]

maybe someone else will respond but - is your OBS 3.9 final drive? and i THINK the 02 Legacy GT is 4.11 FD.

[brentlysubaru]

It's a auto with 4.11 and according to car part the legacy is 4.11 also.

[1 Lucky Texan]

ah - well, my gut says to stay with the OBS axles but, really, it's just a guess. even if length is the same - there may be a spline count difference.

 

fingers crossed you get better replies

Edited November 15, 2016 by 1 Lucky Texan

[idosubaru]

others have install the 00-04 diffs in 95-99 legacy/outbacks without issues.

 

Got a 97 impreza obs. The rear diff is going out

are you sure? that's usually a misdiagnosis and incorrect. subaru rear diffs rarely fail.

 

every "failing rear diff" i've seen ended up being something else. car i just bought was like that - was told it was the rear diff, it wasn't.

Edited November 16, 2016 by grossgary

[brentlysubaru]

I'm guessing that it's the rear diff. When I got the car in Feb it had a bad right rear wheel bearing then about a month later the axle went out in that side the outer joint was frozen solid. I thought it was the diff then because I checked the fluid level in it and it was about empty and what lube that was in there was like sludge. Put synthetic gear lube in and changed the axle.

It was fine for a couple months then started a shuddering noise only when I turned a hard left. I was thinking torque bind but it should do it turning both ways? So when I was fixing the exhaust the other day I noticed that I could turn the driveshaft about a half an inch before it would spin the CV axles. That's what made me think that the rear diff was going bad. Is this the right diagnosis?

[idosubaru]

it still only does it while turning left? 

did you install the FWD fuse to see if the binding goes away?

 

that one directional bit does sound odd, but i'd still guess torque bind first before the diff just based on the words i'm reading (i realize in person can be more convincing).

 

drivetrains typically have slop, so turning before catching is normal.  of course there's limits but it would need some compelling play to be diagnosable.

[1 Lucky Texan]

^^^ yeah, with pinion and spiders and old tripod/DOJ joints - 1/2" doesn't seem bad.

[brentlysubaru]

I "accidentally" tried the fwd fuse a few months ago when I had a flat tire and had to use the dummy spare. It went away for a little while but came back though it didn't seem as severe.

The one thing that I did discover when I was looking at the CV axles I have from a few cars I parted out is that the axle I used in my 97 came out of a 93 impreza and having the 93 axle up against a 95 impreza axle the part where the axle rides on the bearing in the diff is smaller on the 93.

I think I might have discovered the noise. I'll know when I get a chance to tear into it.