1995 BMW 840ci needs replacement rear differential assembly

[Yellowjacket]

I have checked around and the discounted price is ~$1800. Does anyone know if this part can be rebuilt? Or a cheaper source? Or a salvage 840ci in their garage? Thanks.

[mcoupemindy]

Give these guys a call. They do custom diff applications for all BMW's. Maybe they can help you out.

http://www.metricmechanic.com/

[Nick325xiT 5spd]

Is the diff shared with other cars? Like, say, the E32 or E38? If so, those should be readily available for not very much.

[Reach]

These guys know a ton about BMW diffs and may be able to help you as well. Not the cheapest, but I've gotten info from them before.

http://www.diffsonline.com/

[Yellowjacket]

Thanks all. I am following up.

[Yellowjacket]

Just had a wonderful and educational discussion with Teddy at Metricmechanic.com, a family owned business. Teddy was very patient and said he welcomes calls for info. That is very generous of any company.

Metric can rebuild the differential for about $1k and if needed $350 for new internals. It is a nice break from MSRP $2200 for a new one and $1800 after club discount. The labor will cost me 3 hours of labor to remove the old one and install the new one. The cause: Teddy asked me when the front seal was replaced. It was about 2 years ago. He said that after that particular seal is replaced, it is possible that the crush collar was over-tightened which caused the differential to wear. He has had a a number of calls with similar issues and background. BTW The differential box is unique to the 8 series while the internals share parts with the M5 and 540. Again I appreciated Teddy and Metric's help and their expertise. They focus on BMW engines, transmission, and differentials. They have my business for sure.
.

[Bob]

Thats a pretty plausible scenario, differential backlash adjustment is one of the most exacting procedures in auto repair, some call it a black art.

[Yellowjacket]

Thats a pretty plausible scenario, differential backlash adjustment is one of the most exacting procedures in auto repair, some call it a black art.

No kidding. Teddy called it "finicky"... for me the layman. He was very patient with me who have basic mechanical knowledge. I am glad I did some BMW motorcycle DIY tech days, learned a lot and was talked through milestone services and shock replacement.

I can offer all you can eat pizza and beer and wine if the replacement can be done at a tech day.

[Nick325xiT 5spd]

A quick search implies that you can use E32 diffs and that you can use E34 diffs with new output flanges. You can probably obtain those for a lot less.

[Yellowjacket]

Just talked with a 850ci owner and found out that the E38 diff may fit exactly. The 840ci is open and I am hoping to find a limited slip one. That will be fantastic!

[Yellowjacket]

Just spoke with Metrrix Mechanic again about the E38. They said it is not an exact fit. E38 is shorter however a rebuild is still an option.

[Nick325xiT 5spd]

Man, I guess nothing is the same on the 8.

For what it's worth, diffsonline is showing E31 diff rebuilds at $1,195, with a basic LSD build at $1,695. You might want to give Dan a call and ask about it. Tell him Nick sent you if you do - he helped me out a little when I built my race car.

[Yellowjacket]

Thanks. I have contacted Dan.

[uptownautoservice]

Well, A quick search implies that you can use E32 diffs.

[Yellowjacket]

Well, A quick search implies that you can use E32 diffs.

A couple of members have posted this info so far and I need to put up the disclaimer that two shops provided to me: only the E31 case will do. some of the internal parts from other diffs may work.