Tools needed:

14mm Hex - 1/2" drive
1/2" drive Ratchet
Transfer Pump
Jack Stands/Ramps
Low profile floor jack

Drive the car around for a while to warm up the rear diff oil.

Then lift the car and make it level.
Click here to read the entire tutorial

Thanks!

Danny

On the gear oil weight.

how about the pan/filter. Is there a chance that in pumping the fluid that parts of the filter will break away and create an environment for damage? (I could be making this up) Thinking about paying to have this done but it looks so easy. Was thinking I would rather pay and have the pan/filter replaced as well. Also, pumping it in easy? Or does it try to leak out everywhere. I have that same transfer pump, it would be nice if I knew it worked.

There's no filter. Kinda hard to mess this up. Just make sure you use the right and correct amount of fluid.

Did you measure how much you drained out? And refilled it with the same amount?

The opening is your way of measuring the amount of fluid to add. Just ensure the car is level and then begin pumping oil into the casing. When it begins to spill out, you have reached the proper amount of oil.

Tischer sells the oil (P/N taken from Bentley Manual) in 1L containers for $43. Capacity of the diff is (EDIT) 1.0L (NA) or 1.2L (T)

83220397244

My diff. took about 1.2 qts, much more than a 1/2 Liter, and $43 for a Liter of oem gear oil is 4 times the cost of RedLine, and many would consider RedLine to be superior than the OEM. The BMW TIS has it as 1 and 1.2 Liters for non-M E90 diffs.

From Mike Miller's old school maintenance schedule:

You can get the Castrol SAF-XO from Land Rover dealers for ~$12L. Same oil as BMW OEM, at a price comparable to Redline.

Given how BMW is with warranty coverage, I am using the factory spec oil until the warranty is up. After that, I too will be perfectly happy to use Redline in the diff.

Yep, I edited my post. Double checked the bentley manual and it says 1L for non-turbo and 1.2L for turbo cars...I should have

BMW servicer told me these fluid are "lifetime" and don't require replacement.
Thoughts?

As stated before, in car ters, "lifetime" means 100,000 miles, id still change it everytime I change my tranny fluid since I'm down there already. Not to mention, its a nice way to maintain your car if you tend to drive your car hard as well

I found a video of someone using the Asmoil Severe Gear 75W90. Anyone used the Asmoil instead of the Redline here?

i used amsoil severe gear 75w-90.

i measured how much i took out and put back about the same amount. i did not fill until it came out of the fill hole.

At a glance it appears that suction gun is the only way to drain diff w/o major work as it appears that there's a diff mount integral to the cover - true? Sorry for not just looking under car but it is quite cold and wet out and I don't fit under there...

True. You have to remove the rear diff mount to open the diff up from the cover. The only way to get the old fluid out without removing the cover is with a fluid transfer device. I use a pneumatic oil extractor unit. Easy as pie with one of those.

Thanks for posting this. Looking forward to DIY rear diff fluid change.

Hey OP (and anyone else), where did you get that 1/2'' 14mm hex from? That is not a part that Lowes sells for sure. Im curious as I changed my oil/manual trans fluid this weekend but didnt do the diff b/c of this piece. I didnt notice it was such a unique piece, at least to me, until Friday night before changing.

Thanks.

I got the 14mm hex from Amazon, $9.13. I've forgotten the brand or the vendor, but, hey, I'm likely to only use it once or twice every couple of years.

Has anyone considered using full synthetic oil stabilizers in the diff? Seems weird to ask but just throwing it out there. And does the oil need to be full synthetic? I see a lot of brands stating full syn. And some not mentioning it at all. As with all things used in the car, its better to ask than to mess something up and then ask. I was planning on using mobil 1 gear oil at 75w-90 full synthetic, any thoughts?

Thanks for the write up. How many qt do you need?

So the fluid needs to be sucked out? Kinda dumb design...

make sure it is synthetic. We could argue about brands all day but synthetic oil is more stable than dino oil. they do better in extreme heat and cold. if you did use cheaper dino oil i would say the drain interval would be much shorter so it wouldn't be that much of a savings, and why risk it.