Front Diff fluid change: any DIYs available?

07-25-2024

I have a '21 X5 4.0xdrive 87k, and it's time to refresh the drive line fluids.

Are there any instructions or DIYs available for changing the front diff fluid? Been looking all over, but can't find anything.

I know there are separate fill and drain plugs, and that you have to remove the aluminum plate to gain access. Are there any other things to look out for? Do I need to remove a wheel, or fender liner, etc? Any tips are appreciated.

Thanks,

Chris

08-27-2024

Yes... there is a drain and fill plug for the front diff.... that's more than I can say for the rear diff, or the transfer case. They only have 1 plug.

You'll need to remove the cover under the engine, of course.. but otherwise, it's not too bad.

I used a ratchet with a 12" extension, and was able to get to the fill plug through the wheelwell.

01-27-2025

I couldn't find the front differential. Is it under the skid plate?

02-23-2025

muazar3 wrote
I couldn't find the front differential. Is it under the skid plate?

yes it is.

this video is likely for F15. But should be similiar procedure. You can start around 4 minute mark.

03-04-2025

Does anyone know the actual fluid type? There’s like G2, G3, G5 how y’all know what to use? (2021 x5 45e)

03-05-2025

My first post😁

I had my Euro specialist do the Trans, front and rear differential and transfer case. While there also had the coolant and brake fluid changed. Engine oil had been changed 1000 miles before. Car was bought used but these services were never done. My G05 is now living up to the ultimate driving machine for a longtime to come.

03-10-2025

Attaching the procedure from ISTA to the post.

jiggyboiswagg wrote
Does anyone know the actual fluid type? There’s like G2, G3, G5 how y’all know what to use? (2021 x5 45e)

This is also from 2019 software, it might have been updated.

An image attached to this post, provided by the poster

G05 Oil change in the front axle transmission including used oil disposal.pdf

03-12-2025

Very helpful, sadly the PDF is cut from the sides so I can't read it all

03-12-2025

muazar3 wrote
Very helpful, sadly the PDF is cut from the sides so I can't read it all

Thanks for the heads up. I didn't realize I had to print to landscape. I've reuploaded, and looks like it's not cut off anymore :thumsup:

03-12-2025

Bumbleboy92 wrote
Thanks for the heads up. I didn't realize I had to print to landscape. I've reuploaded, and looks like it's not cut off anymore

Thanks for this, really appreciate it

05-17-2025

IH8SPM wrote
My first post😁

I had my Euro specialist do the Trans, front and rear differential and transfer case. While there also had the coolant and brake fluid changed. Engine oil had been changed 1000 miles before. Car was bought used but these services were never done. My G05 is now living up to the ultimate driving machine for a longtime to come.

Great video man, thanks!

06-14-2025

Bumbleboy92 wrote
Attaching the procedure from ISTA to the post.

This is also from 2019 software, it might have been updated.

Anyone know why the fluid spec changed from G2 to G5 in 03/2020?

06-18-2025

Attached two photos the fill plug is on the drivers side you need to remove a plastic cover think it’s 4/5 8mm screw bolts and wiggle the plastic off.

The drain plug is under the skid plate you need a 16mm socket to remove the 10ish bolts plus two 8mm screws at the end and slide it out.

Draining is simple open it up and let it drain.

Filling was easyiah you mine took .9L I used a 500ml fill tool just have to wiggle it in there.

06-27-2025

Just did my front and rear differentials, both with BMW G5 fluid. Front fluid was much darker than the rear in my case.

I had to double check the TIS because when I put 450mL in the front nothing came out of the fill hole, turns out that is by design. The rear still has the standard I'm used to where you fill until a little bit starts coming out of the fill hole.

I've had this tool for doing my E82's rear diff fluid for years, worked perfect for the G05's rear diff as well.
https://www.fcpeuro.com/products/bmw-differential-fluid-extractor-tool-fcp-euro-b3300000

07-02-2025

You filled it with 0.9 L !

Very strange the TIS states either 450 ml or 600 ml
How much drained?

07-02-2025

muazar3 wrote
You filled it with 0.9 L !

Very strange the TIS states either 450 ml or 600 ml
How much drained?

I recently acquired ISTA 4.50.12. Looking it over again, it appears that the name was incorrect previously.

Main work 5 is the same: Check/add front axle transmission oil

Main work 6 is now: Draining/topping up front axle differential oil.

The 'Technically suitable front axle transmission oils' is the same as before.

So, top-up vs drain/refill for the 450 ml vs 600 ml values

I attached newer version here and replaced it on my original reply

G05 Oil change in the front axle transmission including used oil disposal.pdf

07-09-2025

Bumbleboy92 wrote
I recently acquired ISTA 4.50.12. Looking it over again, it appears that the name was incorrect previously.

Main work 5 is the same: Check/add front axle transmission oil

Main work 6 is now: Draining/topping up front axle differential oil.

The 'Technically suitable front axle transmission oils' is the same as before.

So, top-up vs drain/refill for the 450 ml vs 600 ml values

I attached newer version here and replaced it on my original reply

I'm confused reading the TIS, are you supposed to fill it with 450ml or 600ml after draining?

07-09-2025

I guess it depends on whether you have the RB31 00952 or B31 00775 differential?

07-15-2025

Just did the service on my G05 with air suspension. Based on ISTA I think the air suspension diff holds 600ml of fluid.

I had the front on jacks so there was a small upward car tilt.

I measured only 400ml that drained and filled it back up with 450m (an extra 50ml for good measure)
Not sure why only 400 ml drained, but I didn't feel comfortable to fill it with more than what drained.
Hopefully the vehicle is ok

01-12-2026

muazar3 wrote
Just did the service on my G05 with air suspension. Based on ISTA I think the air suspension diff holds 600ml of fluid.

I had the front on jacks so there was a small upward car tilt.

I measured only 400ml that drained and filled it back up with 450m (an extra 50ml for good measure)
Not sure why only 400 ml drained, but I didn't feel comfortable to fill it with more than what drained.
Hopefully the vehicle is ok

Just did mine too. Thought I’d share few points from my experience since this is one of the top threads on Google for this service. Thanks everyone for sharing the resources- it was a big help.

‘21 X5 45e with 85k miles (air suspension)

Rear diff: I was able to pump 850ml out. I put in 900ml then lowered the rear wheels off the ramps and then opened the fill plug to let a bit dribble out and level, before torquing it down.

Front diff: I was able to do the job without removing the stiffening plate; I was trying to avoid buying new bolts - I know many folks reuse theirs. So I did the job from the left wheel well, car on jacks. It was tight but I was able to fit a thin hose, 1/4” OD, and pump out about 400ml from the fill plug. I put in 450ml, like Muazar3, for good measure.

- The front fluid was quite smelly and dark, rear fluid was also dark but still some amber when pouring.

- Realoem says my front and rear fluid is BMW G5. I used Febi part # 184247, which is 70W-80 GL-5 and recommended for BMW G5. I bought 2L and still have 600mL left.

- I still wasn’t able to figure out how to tell if I have the 175AL differential, the one that says 600mL capacity, so easier to just measure what came out. Other threads say that’s the M50i diff that takes 600mL and that makes sense to me, seeing how much fluid came out of my non-M50 diff.

- Overall a reasonable job for a Sunday afternoon. I will likely do it again in 50k miles or so.

Garage

1 Series

2 Series

3/4 Series

5 Series

6/M6 Series

7 Series

8/M8 Series

M2

M3/M4

M5

X1/X2

X3/X4

X5/X6

X7/XM

Z4

BMWi

Front Diff fluid change: any DIYs available?