Differential seals replacement - Differential Tutorial with pics

[LouieD]

In preparation for the trans swap on the Touring, I did the diff seals and took a few pictures along the way. Thought I'd share.

Somewhat clean differential after some serious scrubbing.


Flanges pop right off with a small pry bar.



Not too bad of a leak, but nevertheless a leak. Notice the tab on the side cover in the 12 o'clock position.


Remove the side cover bolts and tap gently. Slip a couple of pry bars underneath and walk it off. Having the diff on it's side helps.


It only takes a few pops from a hammer and a seal driver to remove the old seal.

Old seal out.



Large o-ring is flat. Another source of seepage.




New parts in picture:
Large o-rings (qty) 2 33111214144
Seals with snap clips (qty 2) 33107505602

Not pictured:
Drain/fill plug washers (qty 2) 07119963355
Rear cover gasket 33111211708
Speed sensor o-ring 33111206166
Front/pinion seal 33101214099
1.8 qts. of appropriate gear oil


Fresh large o-ring


New seal installed. Make sure spring is still in place after seal install.


Remove the old snap ring


Install new snap ring. It helps to shove it in, open side down in this position then rotate the clip into it's groove.



Make sure to clean this spacer ring and the surfaces of the housing as well as the side cover. I use a slight coating of gray silicone on both sides of this spacer.


Install the side cover with a little lube on both the o-ring and the seal. Tap it in gently with a mallet or dead blow hammer. Make sure to clock the side covers with the tab in the 12 o'clock position relative to the final position of the diff in the car. Also see third pic from the top.


and finally set the drive flange. It should drop in by hand with a slight snap. You shouldn't have to use much force at all.

[attack eagle]

I just did the stub shaft seal with a seal puller, and then reinstalled it with a dowel and socket

[jehu]

Was there any noise coming from your diff before you did this that lead you to do it or just the leaking? I'm getting ready to head over to a shop and have this noise (appears at 50 seconds) figured out..

[ame=http://s702.photobucket.com/albums/ww23/ArdRi/?action=view&current=PICT0001.flv][/ame]

[LouieD]

Was there any noise coming from your diff before you did this that lead you to do it or just the leaking? I'm getting ready to head over to a shop and have this noise (appears at 50 seconds) figured out..

Just leaking. This diff came from a JY car and is part of my trans swap, so I have not heard this diff yet. It was a bone stock car, with very clean diff fluid so I'm hoping for the best.

[bubba966]

I've got the parts to do all this on the S3.91 large case I have sitting around, though it's probably waay too deep for my M-Sport.

Should be noted that the rear cover gasket is NLA for large case diffs from the dealer. Can get one from Pelican though. BMW no longer uses gaskets for large case rear diff covers. They use a specific type of sealant instead of the gasket.

[attack eagle]

For the record, if the front seal leaks, CONSIDER just buying another diff.

[jessejames]

http://www.realoem.com/bmw/partgrp.d...65&hg=33&fg=10

would I be using one of these diagrams to give me an idea of which part numbers apply to the differential I'll be installing?
I haven't heard much from any of the other 3.15LSD owners as to which seals/gaskets/etc they had changed during their install
if anyone wants to chime in on the subject, it would be greatly appreciated. like I always say, do it once and do it right!

[shogun]

Here more DIY
http://bmwe32.masscom.net/sean750/di...OutputSeal.htm
http://www.bmwe34.net/E34main/Mainte...tial_seals.htm

Question:
How far must the seal be pushed in exactly, when you do not know the exact installation position of the old seal?

Sean750 says in above link: Be very careful what you do, take your time and check often the amount of protrusion of the seal into the diff. I installed it just like the old seal, about 2 mm into the bore. This depends on the removed drive flange shaft. If some wear is present where the old seal contacted the shaft, try to install the seal a bit deeper so that the new seal does not contact the wear groove


Bentley repair manual for E34 page 331-3 says for final drive flange oil seal replacing

1. detach drive axle from final drive
2. pry drive flange from final drive
3. remove wire (snap ring) from final drive opening. Inspect the flange at the point where the oil seal rides on the shaft. Replace flange assembly if there is groove worn in the shaft.
4. pry old seal from its recess using a hooked seal removal tool or a large screwdriver
5. dip new seal in final drive lubricant and drive seal into place until fully seated.
6. install new snap ring in groove of final drive housing . make sure both ends are fully seated in groove.
7. install drive flange by pressing it in by hand until snap ring engages. it may be necessary to turn drive flange slightly while pushing.
8. attach drive and tighten bolts.

tightening torque: drive axle to final drive M10 83 Nm, M10 with locking teeth (always bolts and washers) 96 Nm

The workshop manual says in section 33 11 151 : replacing the shaft seal for drive flange with regards to installation:

drive in shaft seal as far as it will go with special tool 00 5 500 33 3 460 (cover with 4 bolts) or 33 3 420 (cover with 6 bolts).
drive in shaft seal as far as it will go with special tool 00 5 500 33 3 450 (cover with 8 bolts) or 33 3 420 (cover with 6 bolts).

https://www.bmwtechinfo.com/repair/m...es/7410818.jpg

I do not see pics of these tools and probably no DIYer has them, maybe with these tools the seal goes exactly into the position where it should be and not further.
http://www.realoem.com/bmw/enUS/show...diagId=33_1597

[shogun]

From a German E34 forum, original fitting, see the small bore hole, the poster mentioned, distance between ring and end/stop approx. 6,3 - 6,4 mm ...
Looks like the small round holes are important, not sure for what they are. Lubrication or ?

[95525ibob]

Thanks for the links shogun. I just cleaned mine up for a manual swap.

This is a big help.

When you take the drive out of the car with the axles off should it leak all over? Or still be sealed up?

I bought it a few months ago, and looked at it yesterday and fluid is all over. Just wondering if the seals are real bad or if it leaks when out of car.......

[shogun]

I did it on my E32 750 and did not drain any fluid before doing it. The fluid level is apparently not that high in the box that it leaks when you remove the seals. Check in any case the level after replacing the seals.
There is a breather valve on top end of the diff, maybe when you took the diff out it leaked from there.
https://www.bimmerforums.com/forum/s...t-modification

If the breather valve does not work, you get seal troubles/leaks, because of the changes of the temperature of the ATF fluid the volume is always changing and the resulting pressure or the vacuum must be regulated by the breather valve

[q20v]

Here's another DIY (full diff rebuild) I posted on myE28.com not too long ago for a medium case rebuild:

http://www.mye28.com/viewtopic.php?f=3&t=142750

[shogun]

wow, very good pics, thanks

[q20v]

Thanks shogun. It's amateur hour compared to the information you provide, though!

[95525ibob]

If the breather valve does not work, you get seal troubles/leaks, because of the changes of the temperature of the ATF fluid the volume is always changing and the resulting pressure or the vacuum must be regulated by the breather valve


lol yep I had set it down upside down! Vent hole is working!

Going to clean it all up now.

[srad168]

Which gear oil for diff?

[demetk]

Which gear oil for diff?

GL-5 oil. If you have a LSD then you probably will also need an LS additive to reduce chatter or an oil that has the additive already added.

This one looks to be working quite well in the M5,

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

There's also Redline gear oil that people like.

[srad168]

Thanks, Mobil 1 has the additive?

[demetk]

I believe the "LS" designation means it does contain the additive. Get the the spec sheet here, https://mobiloil.com/en/gear-lubrica...c-gear-lube-ls

Depending on your driving style and whether you track the car you can choose between 75w-90 or 75w-140.

[shogun]

I will change the thread title a bit and will add this

BMW Differential Tutorial, with pics http://www.bmwfanatics.co.za/showthread.php?tid=1374

[cirrusblau]

This should be in the DIY section

[srad168]

Are there washers on the drain and fill bolts?

[doctorx69]

pics are all blurry.. cannot see any of them. Can the pics be reposted?

[shogun]

Pics are blurred because of the photobucket new price policy, cannot change it, also the TO was online last time 4 years ago.