Rear end removal and more

[ahlem]

Our local self serve used auto parts yard is having a 50% off sale this weekend.
There is a 540 in there with an intact rear axle assembly.
First question, is it interchangeable with my 535 assembly?
Second question, is it probably a 3.91 LSD?
Third question, how long should it take to remove?
I've done e30's but not e34. I'm hoping it isn't raining.
If memory serves me correctly, I will have to remove the rear cross member mounts, the drive shaft at the diff, the read diff to body mount, the parking brake cables and the calipers or brake lines if I decide to get the calipers.
The best situation would have been to go in there a week ahead of time and get those cross member mounts taken care of. My interest in the project is to avoid doing this to my daily driver and have it out of commission for a couple weeks while I clean and paint everything and get a spare all ready at my leisure. Something is going on in my current set up that's going to need something real soon.
If someone in my general Michigan area has the same deal going let me know, I'd rather patronize a lister.

[shogun]

I have some pics from 2006 when we have done it on my E32 750iL parts car, that will help, basically same procedure http://www.bimmerboard.com/forums/posts/272552/
Do not remember how long it took us as we were not in a hurry.

If interchangeable with your 535: I assume yes.
3.91 LSD : no idea, I am no E34 detail expert

[mattyb]

may as well take brakes and all if available, rotor sizes etc are different from 535.cant say about the rest never had to do it, not yet anyways

[ahlem]

It appears the 7 series has self-levelling suspension? I don't think the 540 has that.
Are my brakes interchangeable with the 540? I have aftermarket rotors and pads. Will this cause e-brake issues? Backing plates different as well?

[shogun]

In that case it was an E32 750iL, all iL = long version have self levelling suspension, but the short version was as stanadrd available with normal shocks. The 540 could have self levelling as an option or even EDC shocks. In this case it would be EDC III, not EDC I, EDCIII is much more complicated and expensive.

To compare your car and the donor car item by item:
Use your car's VIN and that of the donor 540 car (or select model, built year and month) and then compare the part numbers on www.realoem.com

[ahlem]

According to realoem.com part number search, 33311090566 is used in e34 525 touring, sedan, 535i sedan and 540 sedan. All use this same carrier. The differential appears to have a 2.93 gearset in the 540 and 3.43 in the 535. I believe I have a 3.91 from a different car with mine and a 3.43 in my parts bin. I may need a new bearing on the input shaft on the 3.91.
If you spin a rear wheel and both turn the same direction is this a LSD?

[shogun]

BMW Differential Tutorial, with pics.
So I thought I should educate the BMW masses with my knowledge of BMW differentials. Here goes.

Earlier BMW models were nice in the fact that gear-sets and LSD units were interchangeable. Any BMW running the Type 188 (small case) gear-sets in the diff are swappable. Same thing goes for the Type 210 (large case) gear-sets.

Type 188 cars:
All E36 models, except the 3.2lt M3.
All E30 6cyl models.
All E34 models, except the M5 and 540i.
All E32 6cyl models.

Type 210 cars:
E46 M3 and E36 4door M3.
E34 M5 and 540i.
E32 740i and 750i.
All E38 models.
E39 V8 models, could be all models but not sure.

Here are pics of 2 E34/E32 diffs, 1 E34 and 2 E36 diffs. The two large case (type 210) E32/E34 limited-slip diffs on the left. A small case (type 188) E34 diff in the centre. Two 3.15:1 limited-slip E36 diffs on the right.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10811.jpg
Here is an exploded view of the internals of a type 188 open diff.
From left to right: Two output shafts, Open center-portion, Ring gear, Speed trigger wheel, Pinion gear, Input flange, nut.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10812.jpg
Here is the type 188 E34 case, below it is the type 210 E32/E34 case. Note, small case has 6 bolts, big case has 8 bolts.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10813.jpg
Type 210 output shaft, 36mm dia. Type 188 output shaft, 30mm dia.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10818.jpg
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10819.jpg
With the output shaft removed you can see the limited-slip center-portion, it has the allen key hexagonal shaft.
Open center-portions have a round shaft.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10815.jpg
All BMW diffs have tags saying if its limited-slip (S) and the ratio.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10824.jpg
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10822.jpg
Here is the oil I use for Limited-slip diffs.
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10820.jpg
http://img.photobucket.com/albums/v297/gizmo316i/Differential/SDC10821.jpg
BMW changed the differential design on the later models with type 188 gear sets like the E46, these won't work with the type 188 Limited-slip center-portions.

from here http://www.bmwfanatics.co.za/showthread.php?tid=1374

[632 Regal]

No it will not fit. The 540 and M cars have a large case (210) and yours has a mid size case (188) which is sometimes referred to as a small case.

It will be a 2:93 and posi only if special ordered, in most cases it will be an open especially if it had traction control. There should be a tag somewhere on the rear cover indicating what's inside. This information goes for the Mid cases also. It will not be easy to swap a large case for a small one, better to keep looking for a bolt in unit.

No need to mess with the cross member. Output shafts, driveshaft, speedo wire connection and 3 mounting bolts. The rear support mount actually has 4 bolts total and the job goes faster if you remove all and drop the rear mount.

[ahlem]

The PO was a car guy and swapped in what I believe is a 3.91 LSD and had a 3.6x LSD(?) that he included with my purchase. Any chance someone has a chart with gear ratios of the models that had LSD to use for reference?
We see frequent 525 and e36 and some 540 in the yards around here but not too many 535. The chart would help zero in before a potentially muddy crawl under the car to find and clean off the tag. I have 6 bolts on the side cover.

[shogun]

some here http://www.vinesauto.com/diffratio.htm

and the rest should be in the shop manuals, I assume under specifications https://www.bmwtechinfo.com/repair/main/

[ahlem]

I was able to hoist the rear of my car to get a good look at things finally with a semi-dry driveway.
I have an uncomfortable amount of vertical play when I push up and down on the input shaft at the front of the diff. I also have radial play and clicking when I rotate the rear tires. When I hold the output flanges, most of the play and noise is in the CV Joints. With the input play, I may be changing back to my 3.46 LSD and replacing the axles while I scrounge up a second rear end to do the camber/caster mods. Does this seem like the best way to go? Once all this noise is gone, something else will climb to a high priority I'm sure.

[632 Regal]

Vertical play is wear in the pinion bearings or the preload nut got loose. I did mine with loctite since the new collar nut was late (old chevy method). 6 side bolts indicates the mid or small case. The 540 and M cars have 8 I believe. You might be able to simply tighten the pinion nut using loctite to snug the bearings up (+ about 1/32 turn) and be good.

Are you sure the play isn't coming from the joint itself? That amount of play in a differential would be letting the world know something is messed up when driving it. The fluid will look like silver pancake fluid too.

[genphreak]

OMG. All this diff talk and mine blew this morning. Drove 2m up the driveway light acceleration only from rest, and...

"Pannng, crunchhhh, click, click, chick chug, chug..."

It wouldn't go forward, backward. rear wheels jammed on the slope.

The poor ol' girl. Like a faithful old dog, she came home to die the day before and couldn't get up in the morning.

Need to get a new diff now, something 2.92-3.23 me thinks. Hmm... maybe it was all the talk on bimmernut making her jealous. 'Get me an LSD' she was saying...

[ahlem]

I'm hoping it's the loose nut syndrome.
On realoem they show 23211490120 securing plate and 33121744368 clamping bush.
Would I need these both if the nut had worked loose?

[632 Regal]

The clamping bush is the crush collar, you should not need that part... yet. To replace it you will need to take the differential pinion out. If it is that loose you most likely have some serious damage to inspect for inside.

[ahlem]

UPDATE I opted not to go with the 540 set up for many pretty obvious reasons. Mostly the gearing is not what I'm after. I decided to replace the rear axles to get rid of the radial play. A car with 410000 miles has all kinds of things that need routine maintenance. While under there, I noticed my Racing Dynamics(?) sway bar ends were wallowing out the thin metal brackets on the rear control arms. This is probably my source of rattles. I will weld on some thick machined washers and get longer shoulder bolts and probably replace the end links. They are currently Heim style. I do have a set of OEM style somewhere in the parts department. Of course #12 axle bolt gave me trouble and had to have the head cut off. I did hit the cool double washer with the grinder so I am wondering if I can use regular washers without major fear of being unbalanced? I could cut the good part off and tack weld the washer to the remains of the double washer or do it right and order a replacement. Anyone else have the hole wallow problem before?