Rear Differential Woes........ 1989 530i

[jasshrie]

Hey guys, hoping that someone here knows my problem... I just bought a 1989 530i 5 speed, German spec car and the rear diff is blowing oil out the seal around the input shaft. It also makes a horrible scrubby grinding noise when coasting down in gear. I'm assuming that the rear diff is scrap metal... if not, please drop me a line with some info. The car has about 300k kms on it.

That leads me to the second question... I yanked the rear diff out of a 1989 530ix in hopes that I might be able to use the think. I am guessing that it might have a different drive ratio, but not worried about that as long as it would work, it mounts in the same way as the original. However, I noticed that the ix version has a hydraulic line coming into it, and a slightly different electrical connection. I am guessing that the hydraulic line is for a locking rear end? Is it possible to use that rear end and just either lock it up or leave it open? or am I just ?

Thanks! Be easy on me, its my first post to this forum and this is the first BMW I have owned....

[Paul in NZ]

welcome to the site.I cant help with your question but welcome any way

[632 Regal]

good question, I dont know anything bout German spec cars.

[BillionPa]

530iX? i thought only the E34 525 had a 4wd model

[Bill R.]

ix and it would be newer than 89

530iX? i thought only the E34 525 had a 4wd model

[jasshrie]

Which probably means that I'm outta luck with the rear diff, but the normal 525i has a totally different rear diff, which is what threw me off on that one...
I will post some pics of the ix rear diff later... its really close to the one in my 530i, but then again, slightly different... maybe it will still work tho
Both cars are German spec, but in drivetrain components I don't assume there is a difference.
Thx.

[Ross]

Just a thought, but why screw around changing a diff that may not even fit when all it sounds like is a pinion bearing?

[gale]

A couple more ideas:

There's a small vent in the upper-right corner of the back cover. If that's clogged, pressure will build up in the diff when it warms up & maybe force fluid past the seals:

http://www.nmia.com/~dgnrg/diffvent.jpg

There's a metal dust shield on the input hub, right next to the case. It could be scraping & making the noise. The nut that holds the input flange onto the pinion might have come loose & that would explain both the scraping and the leaking. You'll have to take the end of the driveshaft off to get to it.

[Paul in NZ]

530??could it be a 3.0 version of the m30?,i know the UK had some cars with that engine...

[jasshrie]

well, I took out the diff on the 530i to realize that the output shaft flages had different diameters, so I tried to swap em but the splines on the 530 are about an inch longer and it didnt work... so no luck with the 525ix diff...

so later yesterday afternoon I dropped a rear diff out of a 535i since the output flanges are the same. however the input flange is different (and the whole diff is about 25mm longer, which means the driveshaft has to be that much shorter). I thought no problem, I will just swap out the input shaft flange... until today when I tried it... the input shaft on the 535i is about 2mm larger in diameter it appears (32mm nut instead of a 30mm) so I can't swap just the flange.... now my latest and greatest idea is to grab the whole driveshaft from the 535i and stick it in the 530 in hopes that this will work. I guess they have the same carrier bearing and I hope the same transmission mounting flange...

then this afternoon when I crawled out from under the 535i again I noticed that there was an "M" badge on the front of the car...... not sure if thats why the input flange is different or not (here in Germany many many cars have "M" badges just for looks). Oh well, any input is greatly appreciated.. Please call me if swapping the driveshafts is ..

PS: the input shaft bearing on my old diff has about 3mm of play... and the speed sensor was COMPLETELY covered with silver oil (AKA metal flakes).... I think that one is done.... it is the bearing making the grinding noise, not the little shield. however, if anyone thinks that swapping that bearing might be my easiest way out of the sh!thouse, I'm all ears. seems that the 525ix diff has the same bearing, maybe I could just swap em?