Diff mix up

[smonkbmw]

im gonna sell my 3.91 small case. any interest? $180 shipped pm me.

mods ill make a official FS thread, just wanted to get it out there.

[Mr Deagle]

people on e30 tech blow them up all the time

i have never blown up a diff, but my open one is getting there

[e30_325es]

My 4.10 is a small case. You make it sound like the first time you do a burnout w/ one, then it will blow up, which is not true. How do you know that yours wasn't just an uncared for diff?

[Mr Deagle]

Yup, I've got a small case 4.10 bolted up in place of my stock 2.93lsd. Not an issue at all.

And "burn outs will blow up 4.10's"? My ass:


That's a 2nd gear burnout from a chipped eta.

edit: dont do burnouts or you will blow the small case diff up

anything about 4.10s?

no

just keep doing burnouts, and watch the spider gears go bye bye

ill keep the small case in my turbo car, and ill take pics of the spider gears floating around in the diff

[e30_325es]

Yup, I've got a small case 4.10 bolted up in place of my stock 2.93lsd. Not an issue at all.

And "burn outs will blow up 4.10's"? My ass:


That's a 2nd gear burnout from a chipped eta.

[tophertii]

Thanks, for the info. Seems obvious now that you mention it. This is the first time I have found this info and as I have learned I'm not the only one that has faced this problem. If by chance you ever make it to SLC Utah the beer is on me. I may have an LSD yet!

[Rocla]

Someone enlighten me and tell me what mistake I may have made installing it.

Ever wondered why there is a sliding joint on drive shaft?

All e30 diffs do interchange, if you replace typ168(small case) with typ188(med, e30 "big") or vice versa you must adjust drive shaft lenght, because the pinioin "nose" is different in lenght.

Typ210 diff however will not bolt to e30 subframe.

[tophertii]

I'm not sure were the added length comes from, the flanges seem the same. It is hard to find consistent reference points to measure. I think if I place something like a large flat piece of wood on the end of the diff flange and measure straight back to the mounting holes I can take pics and show the difference.

I was pulling my hair out at 1:30 am the other night I quickly tried this with a piece of 2"x 10". I hope to try this again with a better piece of wood or something more suitable.

As I said I would love to be wrong. I will try to get some pics up in the next couple of days or at the latest by the weekend.

[crunk3]

I own a 318is, small case 4:10. I just bought a med case 4:10 lsd out of a 91 vert auto. No fit! If you mesure from the end of the diff flange to the center of the upper mounting holes there is about a 1/2" difference. Damn I need a new diff!

Il buy your diff off u if your gonna sell it :D

Are the input flanges different? I would love to see pix.

[tophertii]

I'm going to document this with pics and post it. I spent literally hours researching wether a med case would fit or not, this site and others. I purchased the diff only after I felt certain that it would fit.

I tried installing it three times and couldn't line up the diff holes with the sub frame. I finally decided to reinstall the stock small case. Bolted up in minutes with no such problems. I later found posts from people with the same problem. It is like the drive shaft is too long.

I would love to find out that the I made a mistake at installing it. I bought the diff and a salvage yard and they do not offer refunds. I also dumped in 25 bucks of Redline fluid.

Someone enlighten me and tell me what mistake I may have made installing it.

I own a 318is, small case 4:10. I just bought a med case 4:10 lsd out of a 91 vert auto. No fit! If you mesure from the end of the diff flange to the center of the upper mounting holes there is about a 1/2" difference. Damn I need a new diff!

You have a different problem. This should fit perfect.

uh oh, looks like im keeping the subframe from my parts car........for my 318i (84)

No, you are correct. A large case 4.10 bolted directly into my 84 318 subframe.

[Mr Deagle]

uh oh, looks like im keeping the subframe from my parts car........for my 318i (84)

[tophertii]

I own a 318is, small case 4:10. I just bought a med case 4:10 lsd out of a 91 vert auto. No fit! If you mesure from the end of the diff flange to the center of the upper mounting holes there is about a 1/2" difference. Damn I need a new diff!