e30 ix differential problems and questions

[MKorodini]

So I have a 91 ix manual with a differential problem. I've had a LOUD whining noise above 25 mph for sometime now. I wasn't sure if it was coming from the transfer case or rear differential. So I jacked up all four wheels and found the noise with a stethoscope. The differential is whining like a 3 year old. Next thing I'm gonna do is take it out for a rebuild. When I checked to see if the limited slip works I found out it doesn't. I had a friend hold one rear tire and I tried to spin the other. I spun the tire no problem while the other stayed stationary. Does this mean my viscose is bad? Can a faulty viscose be the culprit for the whine, or is a bearing more likely? I've searched a bunch of threads and can't find any info that will help me. Any info from any gear heads out there is greatly appreciated. Thanks

[Killacortes]

Was it gear when you spun the tire?

[MKorodini]

neutral and e brake off

[Kershaw]

Front diff, center diff, or rear diff?

[nando]

you have to hold one rear tire and one front tire and try to spin the wheels. if you hold a rear tire while you try to spin a front, and the other is free, you'll spin the other front wheel.. best thing to do is jack up the rear and try spinning a rear tire with the front on the ground, or do the jack test.

for the diff - rebuilding isn't going to be cheap. I'd just get a used one and call it a day. Maybe rebuild it on the side if you're bored..

[MKorodini]

Kershaw, rear diff.

Nando, I've read countless replies you've sent people and your knowledge amazes me. Thanks man.

[mybimr]

for the diff - rebuilding isn't going to be cheap. I'd just get a used one and call it a day. Maybe rebuild it on the side if you're bored..

I have the same issue as OP. I know it's the input bearing since I could feel it grind when I spun it by hand with the driveshaft removed. I believe it's the last bugger in the drivetrain I need to touch in order to get it driving like new. I've replaced the tc, guibos, shifter linkages, all 4 wheel bearings, and drive shaft. So I don't believe there's anything left but the diff. all cv joints are good too.

The problem is, I haven't been able to find one used. Bavarian Auto recyclers has a couple, but I believe they're asking $600+ for original units that haven't been rebuilt, which is what I estimate a rebuild would be (let me know if I'm wrong). So, I too am thinking of rebuilding what I have. My vc in the diff works great, and believe the only problem is the bearings. The seals don't even leak, but I would replace them with the input and output bearings.

[nando]

Try ebay

[MKorodini]

Will anyone by chance know if an 3.91 from an e32 will work on an ix. I know I gotta switch out the cover. Should I stick to a 3.91 ix specific? I looked up both on realoem and the internals are not similar.

[ColinGreene]

If its from a E32 it may have the large diff. it may not be compatible.

[nando]

it won't fit.

[jute91]

https://www.metricmechanic.com/pdf/Differentials.pdf