[AlanAZ]

Originally Posted by Multibimmer

Since the drain and fill plugs come with an o-ring built in, should these be replaced when doing the fluid dran-and-fill? And are the drain and fill plugs identical? Thanks.

My diff., and I believe every non-M diff., has only one plug, a fill plug. And why this thread is about pumping out the old gear oil, thru the fill hole. You want to post a photo of your drain plug.

[bvanderhaar]

Just did this DIY this evening on a 328xi 3/08 build date, 94k miles. Fluid that came out smelled awful - I'd suggest changing it sooner. I replaced it with Red Line 75w90. Thanks for the clear instructions. I got the same pump from Harbor Freight that is pictured.

I'm not sure if it was due to this or not, but a whining noise and some subtle hesitation/vibration upon long/wide turns at about 3K RPM seems to have disappeared. Could be me imagining things. The whining/vibration was very subtle to begin with.

Edit: from a cold start (36 hrs) the whining / vibration is still present. I still think this was time well spent - the old diff oil was in terrible shape.

[AoS810]

has anyone run into any issues using redline 75w-140 (instead of 75w-90) fluid for their rear diff?

*EDIT* reason I ask is I had my diff fluid changed recently by an indy and they put in Redline 75w-140, but I just checked the Redline application guide for my vehicle and it does mention 75w-90.
*EDIT2* I found the following Q&A on bavauto: https://blog.bavauto.com/10933/bmw-d...-applications/ seems like there is no harm running LS fluid (75w-140) in a non-LS differential (my 328i), may potentially have negligible mpg loss.

[GEOS07335i]

Originally Posted by jay_3

Has anyone done this on a 3 series with awd? I have a e91 328xi and theres a huge A-Shaped frame which is blocking my access to the fill/drain bolt on the rear diff.

It looks relatively easy to remove (3 bolts), but I have no idea what the torque specs are or what it's even called for that matter.

Will post pics if needed.

Anyone comment. I have an 08 E93 and i have what looks like an x-frame that intersects right at the center of the diff. Unfortunately I cant get access to the drain plug. Anyone do an E93 please tell me if you had to disassemble the x frame braces to get access. Also on mine the plug is towards the front of the car. Not exposed to the rear like I'm seeing in other vid's and pictures where you can easily access the diff fill plug from behind the bumper. Do they have different housings. I thought an E90 -E93's were all the same?

[330guy]

did you use additive for this? got Mobil 1 synthetic 75w-140 and says It already has limited slip additives in there

[nuke21]

I recently did this and my car only took about half a QT. The car wasn't level, the back was about an inch higher than the front. Maybe I should drive it around the block and then recheck it. I would imagine the inch higher in the back would allow me to add more than normal before coming out. Maybe only half a QT came out and I just think it was more than that. Guess I will do this again tonight to verify.

[chadjones99]

Originally Posted by HRC

BMW says "lifetime" which is umm...whatever. In car talk, lifetime means 100k miles.

Danny

I believe life time means 100K also I seen it somewhere on a service book

[mgorman87]

Changed mine today. Pretty easy. Very messy. Easier putting the car on jack stands

[chadjones99]

Ya I change it too, to bad it doesn't have a drain plug , hate pumping the oil out.

[chadjones99]

looks like my 328 has open diff and not posi trac

[stephanporsche]

My E90 has @85k miles and I recently changed my transmission and differential fluid as well as several other repairs. The transmission fluid was dark as expected with the miles however I was extremely surprised the differential fluid looked almost new, without LSD or driving the car hard the rear differential just doesn't get a lot of heat, either way I was good to change just surprised because in my two Porsche's I change the differential fluid every 30k and it is always dark.

[Voda]

How much oil do I need for a e90 20d?

[gde061]

Read through the whole thread... great info. It looks like HF has the 14mm hex in a 3/8 + 1/2 set for relatively cheap. Going to pick that up and try this job tonight. Quick question before I get out the wrench though... the Castrol spec SAF-XO (presumably the OEM spec?) says it is GL-5. I have some GL-5 Mobil 1 synthetic 75w90 branded "LS" (presumably limited slip) hanging around my garage and would just as soon use that ...

I wonder if anybody know if there is something peculiar to SAF-XO that would make a plain vanilla GL-5 screw up this BWM diff. (I'm working on a 335xi). From what I can tell from the Castrol spec sheet, the thing about SAF-XO is that it's supposed to play nice with mineral based (petroleum) oils, important if you are working in a potentially cross-contaiminated application. Maybe that's necessary for working on older BMW's?

Any and all insights appreciated!

[gde061]

Finally got this done tonight as I was putting on the winter tires and decided to just put the whole car ('08 E92 coup) up on jack stands. That was where trouble started. I used cut 4x4 blocks in the rear behind the jack points and jack stands in the front. Even though the jack stand was on the stupid rubber jacking point, when I went jacked up the other side, it shifted and went on the rocker panel facia and deformed it. Lucky it didn't crack. Do yourself a favor and use blocks or at least put a piece of wood on top of the jack stand... don't rely on it "hugging" that plastic jack point.

Next problem... only go about 1/2 cup (so maybe 1/8 of a quart) of the diff fluid out using the crummy harbor freight style transfer pump. I used the oil tube that came in that kit, which is 1/4" tubing. I had warmed up the diff fluid with a little drive but by the time I had things jacked up it was pretty cool. The pump struggled to move the material, and at one point it seems like there was semi-solid resin coming out with the diff fluid. IDK how that's possible, but I got out what I could and then pumped in about 3/4 quart of Mobil 1 rear diff. fluid. If you are using 1/4" tubing, don't let it go straight back in the diff... it can get snagged and then you will be trying to work it out without leaving behind a stub of plastic tube in your diff. Don't ask how I know. I had an idea about how to get the tube to point down into the bottom of the diff is to wrap it loosely with a wire and then bend the wire down... not enough to kink the tube, but enough to make a "hook" shape. But again, watch out for snagging. It worked out in the end, but be cautious.

Finally, trust your arm on the final torque. I saw 60 N-M in the Bentley's but my stupid HF 1/2 Torque has Ft-Lbs and some other thing with a K. Don't get mixed up and use 60 Ft-lbs on it. That would be bad. I had the wrench set at 60 Ft-lbs and was like, now way, this wrench is garbage, it should have flexed by now, so I went back and double checked the units, and the right torque was 44 Ft-lbs, which is 60 N-m!

Too tired to take it for a spin now... gonna leave it overnight with some cardboard underneath to see if anything is dripping. Also mine had no crush washer, just some green lining material on the inside lip of the plug, which seemed intact so I didn't mess with it.

[4foothill]

Probably a stupid question but am I ok to chuck 1 quart (0.95l) in a diff that needs 1 litre of fluid? Can't imagine that 50ml extra will do much difference but I'm a sucker for precision.

[chadjones99]

I would think the 50 ML would not matter, but if you live in a very hot climate , oil does expand when hot... so you have a vent on your rear end... might bubble out a little ?

[Gregrobin]

Only other piece of advise I would add is make sure to loosen the fill plug before you remove the drain plug. You don't want to get stuck with an empty differential and then can't remove the fill plug.

[Phil325i]

Originally Posted by Gregrobin

Only other piece of advise I would add is make sure to loosen the fill plug before you remove the drain plug. You don't want to get stuck with an empty differential and then can't remove the fill plug.

Good advice...except that most 'Lifetime Fill' BMW diffs have no drain plug.