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 crazy?

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 crazy if swapping the driveshafts is crazy.. :)

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?

[jasshrie]

http://road.meatball.net/gallery/1989_530i/DSC00481
Forgot to post the pics! Here is the diff from the 525ix and the 530i side by side... note the difference in the output shaft flanges..

http://road.meatball.net/gallery/1989_530i/DSC00484
and here its possible to see why I couldn't just swap em. the splines are different lengths... :(

Here are some pics of the 535i rear diff compared to the 530i rear diff... noticably different.... and more trouble for me...
http://road.meatball.net/gallery/1989_530i/DSC00490
Just click the forward arrow in the gallery to see other views...

[jasshrie]

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

Yeah, the bearing is definately toasted... its got about 3mm of play and the input shaft just kindof wobbles around in the bearing... how difficult is it to swap that bearing out? I guess the ix diff has the same bearing (input shafts seem to be the same size at least). Maybe the shaft is damaged badly tho as well...
I am known for taking small problems and turning them into big repairs... next thing you know I will be swapping the engine to fix the diff! J/K.. i hope...

THX!

[632 Regal]

http://www.bimmer.info/~regal632/rearend.html

[jasshrie]

http://www.bimmer.info/~regal632/rearend.html

Thanks for the link! At least it helps give me confidence.... :)

[jasshrie]

So, here is a pic of how I left the differentials a couple hours ago...
http://road.meatball.net/gallery/1989_530i/DSC00506

Wish me luck.

I do have another question tho, what is the easiest way to get the pinion out? is it possible to do it without destroying the seals and bearings?
Is there a bearing pressed on from the front while the pinion is in the case? (as well as the bottom bearing?)

I left both cases with only the pinions still in place- thought its better to ask than go wacking away with a hammer :)

Thanks in advance...

[jasshrie]

http://road.meatball.net/gallery/1989_530i/DSC00506

Wish me luck.

I do have another question tho, what is the easiest way to get the pinion out? is it possible to do it without destroying the seals and bearings?
Is there a bearing pressed on from the front while the pinion is in the case? (as well as the bottom bearing?)

I left both cases with only the pinions still in place- thought its better to ask than go wacking away with a hammer

Thanks in advance...

[jasshrie]

Hey guys,

For anyone thats interested, I am almost finished with the repair.. Yesterday I swapped the rear diff and driveshaft from a 535i into my 530i and everything mounts up.
http://road.meatball.net/gallery/1989_530i/DSC00509
I just hope the donor rear diff is decent. I will top up the fluid in the rear diff and take it for a spin as soon as I get the front suspension back together (went ahead and changed out the bushings while I had it up in the air).

I'll post a followup later.

[632 Regal]

good man, i knew you could do it. did you try to swap the pinion bearings or just swapping the whole unit? If so I sure hope the ratio is the same!!!

[jasshrie]

Yeah, I ended up swapping the rear diff and the driveshaft from the 535i since it slid right in without some crazy modification.... But not before I started to swap the pinion bearings from the 525ix and 530i rear diffs... those are still apart, and actually both are in pretty good shape. I'll probably just junk the 530i one with the bad bearings, and put the 525ix back together. Its got that cool hydraulic lockup system :)
Maybe I can find someone who needs one of those.

Anyways, the car is so quiet now with a good rear diff. Plus the final drive ratio must be a little bit lower cause its got more grunt and is a fair bit quicker off the line (although I haven't calibrated my seat-of-the-pants accelerometer in a while :) ).

Thanks for your help guys.

[jasshrie]

Turns out that the rear diff I put in was bad as well, it only lasted about 30km.... no now back to square one.

What is the best way to remove the pinion bearings? Or to get the pinion out of the case?

Do you press the pinion out towards the rear of the case to free up the front bearing, then press the rear bearing off the pinion?

Looks like I might just rebuild the original, since I've got it all apart except for the pinion...

Thanks

[632 Regal]

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