[liamh]

Thanks, just got round to installing ISTA. You're right, looks straightforward.
Just need to work out how to make it easy to get the pump out now 🤔

[GoldenWest]

Originally Posted by CirrusSR22

I have a 2017 MINI Clubman ALL4 which is the same drivetrain.

It appears to me that Hypoid G3 is the proper fluid. For that it’s just a easy drain and fill per the TIS. Actually not a drain, you have to suck it out the fill hole. I used my oil extractor with a smaller curved plastic hose on the end to dip it into the bottom of the differential.

RealOEM Shows Hypoid G3
https://www.realoem.com/bmw/enUS/sho...08#33108740374

New TIS is a bit less clear, as you mention. G1 vs. G3
https://www.newtis.info/tisv2/a/en/f...-drive/1EFiDSn

Genuine G3 is about $50 per HALF LITER. Yikes. I recently swapped mine out with MOPAR Synthetic Axle Lubricant which is the same 70w-80 GL-5 spec as the Genuine BMW G3. MOPAR part 68227765-AB. It’s about $25/quart. Although, I probably only sucked out 1/2 liter, so maybe one 500ml bottle will do?

Then there’s a separate fluid reservoir for the AWD clutch system within the rear axle unit. That’s BMW “HOC” fluid. “Hang on Clutch”. Looks like that’s the one that needs the dealer computer to both bleed and calibrate it. A bit more mythical on the Internet. Not much consumer-level info on the AWD system used in the newer FWD based BMW AWD vehicles yet.

I have a Foxwell NT530 computer/scanner and unfortunately it doesn’t have this function.

I also swapped my transfer case fluid (PTO box). That’s just plain-old synthetic 75w-90 GL-5 synthetic from what I can tell. I used AMSOIL Severe Gear Synthetic 75w-90 GL-5

FWIW, from above, the transfer case is not 75w-90 GL-5.
Over many years I’ve generally stuck with Redline oils; in part due to the quality, and for they’re excellent, and easy to contact tech dept.
On my ‘17 X1 x-drive, Redline’s recommendations (attached image) is MT-LV 70W/75W GL-4 Gear Oil for both the transfer case and rear HOC “Hang On Clutch”, transmission is D6 ATF, rear diff (final drive) spec is 75W/85 GL-5 Gear Oil, but I substituted 75W/90 for better protection.

Castrol gear oils are mentioned elsewhere in this thread. The SAF-XO is 75W/90, and Castrol (not Pentosin) SAF-XJ is 75W/140; both are GL-5 gear oil formulations for differentials.

[X1BMWR]

Originally Posted by Skyline2.0

Thanks much for confirming fluid compatibility, Jack. I called another Parts Dept and they also said the C-SAF-XO 75W90 is appropriate for my XDrive model. Their system did show Synthetic OSP as the proper fluid, but listed the C-SAF-XO part #.

I drained out ~0.4L of transfer case fluid and put in about the same. Fluid was quite nasty. As others noted, drain and fill is straightforward and simple. Most time consuming part was getting the car level and removing one of the bracket/aluminum tube near the passenger/right front CV axle. I spent an inordinate amount of time fussing with 1 bracket due to space restrictions. Pic of the tube removed (separate bracket not shown) and fluid color attached.

Word of caution - There's an electrical component (I believe the starter?) right near the transfer case, which you should not touch with any metal objects. I must've accidentally made contact with my ratchet after cracking the drain plug loose and sparks flew suddenly. Needless to say I was more careful going forward.

Also performed transmission fluid drain and fill twice using Febi Bilstein's ATF 6 fluid (Part # 29934) on my Aisin 8-speed unit. ~3.5L drained out. Color that came out wasn't too dirty. Shifts are definitely smoother and notchiness on inclines seems to be gone.

Checked fluid level @ ~45 Celsius using scan tool. Shifted through each gear twice and held it in position for 2 seconds to get the fluid fully circulated. Took final measure while car was running and waited until only a slow drip came out of the overflow plug.

For transmission service, tips for future members that attempt to DIY this:
1. Get a good 17 mm hex socket and apply a good amount of upward pressure to remove the large overflow plug. The hole is not very deep and there may be a risk of rounding out the overflow plug if you're not careful.
2. Clean off top of transmission before removing fill plug. I had loose particles of dirt and debris that I cleaned off to ensure junk didn't fall into the transmission hole.
3. Get a long extension and long funnel (or fluid extractor syringe pump) to make your life easier when filling with new fluid. The fill hole is fairly deep in the engine bay and a standard funnel will make pouring a bit more difficult.

Thanks to all that contributed to this thread.

Thanks much for sharing this information.

I tried to reach the fill plug as mentioned, but went a different route, which may be a bit easier and without the risk of getting burned.

I removed the intake snorkel and the bottom of the air filter housing. 3 bolts total to acces the fill plug to the right of the TCM?
You will need a long funnel to make pouring easy. Hopefully this will help someone.
Last picture from the fluid that came out of the transmission @100k

[dentprotony@gmail.com]

Thats a transmission fill plug, please dont mess up

Originally Posted by X1BMWR

Thanks much for sharing this information.

I tried to reach the fill plug as mentioned, but went a different route, which may be a bit easier and without the risk of getting burned.

I removed the intake snorkel and the bottom of the air filter housing. 3 bolts total to acces the fill plug to the right of the TCM?
You will need a long funnel to make pouring easy. Hopefully this will help someone.
Last picture from the fluid that came out of the transmission @100k

[X1BMWR]

Originally Posted by dentprotony@gmail.com

Thats a transmission fill plug, please dont mess up

Thanks for confirming that being the fill plug of the transmission.
Yes I was doing a transmission drain and fill and commenting on the second part of the post.
The S- drive has also a transmission fill plug near the starter pointing to the rear below the exhaust. Maybe I misunderstood but this very hard to reach. I could not find any directions or pictures on the internet, so that is way I posted this picture.
Happy New Year

[46-90-48]

Hi Gents,

planning to DIY the haldex maintenance and looking for torque numbers.
Without TIS it tough to find those, - does anybody have torque figures for main haldex unit (those four bolts)?
I've see one of youtube videos on that, but only side cover plate torque numbers were mentioned, but not the main haldex unit.

Thanks!

[Skyline2.0]

Originally Posted by 46-90-48

Hi Gents,

planning to DIY the haldex maintenance and looking for torque numbers.
Without TIS it tough to find those, - does anybody have torque figures for main haldex unit (those four bolts)?
I've see one of youtube videos on that, but only side cover plate torque numbers were mentioned, but not the main haldex unit.

Thanks!

If you're asking for the torque spec for the 4x bolts that hold the "hang-on clutch" to the "clutch housing", it's 75 Nm and they should be tightened in a crosswise pattern.

[46-90-48]

Originally Posted by Skyline2.0

If you're asking for the torque spec for the 4x bolts that hold the "hang-on clutch" to the "clutch housing", it's 75 Nm and they should be tightened in a crosswise pattern.

Thank you, SO MUCH!
That's exactly what I was looking for!

[GoldenWest]

Correction on your fluids; 70W/75W GL-4 Gear Oil is used for both the transfer case and rear HOC “Hang On Clutch.
In addition, BMW calls for 75W85 GL-5 in rear differentia; although I personally use 75W90 GL-5 as you spec’d above.

[stefdeath]

Originally Posted by X1604M

Can anyone share how to calibrate the HOC pump after changing the oil using ISTA+?
I have never used ISTA before. I read some saying it can be just sucked out and fill.
Should I calibrate the pump with ISTA or just suck out and fill?
Any advice is appreciated.

ISTA says:
1. replacing hydraulic pump of rear axle diffrential - required follow-up work - Carry out the service function " LMV: Calibrate the pump motor" ( I think it is also required after removing the pump from housing )
2. oil change or replacing HOC clutch - required follow-up work - Carry out the hang on clutch oil bleeding routine. Service function--> Drivetrain-->Longitudinal distribution-->Bleeding
Waiting period of 60s
Repeating the service function bleeding routine.

[stefdeath]

Originally Posted by nalin007

I also couldn't remove the pump when i was trying to change clutch oil in my 5 gen haldex on my BMW f48.

I wonder if the removing of cross member on rear axle support would help to extract the pump. See picture attached.

With an oil suction syringe it is possible to extract only about 250 ml of oil from 520 ml that reside in the clutch. Haldex has several oil compartment and making pauses between oil suction (about 5 min) may help to extract more oil. The oil need some time to flow from one camera to another. Unfortunately, i didn't come to this idea when i was changing the oil.

As per TIS, even if you just want to top up the haldex oil to the maximum level you need to perform the air bleeding and clutch calibration . It is easily done if you have access to ISTA or another diagnostic software that support this operation.
I assume that the bleeding can be done by making the pump run for a minute by driving some kms, but to perform calibration you need specific software. I would't omit this step as it in some cases it is required for correct function of clutch. I suggest to do air bleeding first and the the calibration.

When i was performing the air bleeding and calibration i heard some discontinuous squeak produced by pump right at the end of each operation. Did someone experienced the same when doing it?

After 70 000 km the oil in haldex of my bmw was like a petrol. It is annoying that there is no way to drain the oil completely and easy remove the pump to clean its filter on BMW f48. I think it worth doing at least partial oil replacement though suction by syringe on every motor oil change if there is really no way to remove the pump.

Please, share your experience.

Complete workflow:
- Open screw plug
- Slowly top up the HOC Oil until it escapes from the opening.
- Wait for 5 minutes (The differential clutch consists of several oil compartments. In order to guarantee equal filling of the oil compartments, the waiting period must be strictly observed)
- Top up oil again.
- Tighten the screw plug hand-tight.
- Bleed the clutch of the rear axle differential
- wait at least 30 sec
- Calibrate the clutch

- Open screw plug (Oil must emerge from the opening)
- Renew the sealing
- Apply screw plug (10Nm).

Could somebody confirm that procedure mentioned above - toping up oil in horizontal position - allows to put 520ml of fluid to the HOC unit ? I am asking becouse my mechanic changed fluid according the YT:https://youtu.be/JBpFaFo3JCc?si=g-DKH_RsvGBE74kC and even after ISTA bleeding procedure he was able to put in only about 350ml of fluid.
As I've seen in ISTA manuals ( same as TIS ) BMW recommends to ( in simply words) unscrew HOC and swivel to the vertical position:

https://zapodaj.net/plik-4y6ev5zo32

Than ISTA says to fill HOC with oil in this position - it looks more possible to put there 520ml when filling plug is rotated -on the top of pan in this position - not on side :/
Right now my x1 is running on 350ml of fluid in HOC , no cells on the dash, nothing strange happens but I am worried if in long therm it can cause some damage to HOC clutch.

[petered]

Originally Posted by 46-90-48

Thank you, SO MUCH!
That's exactly what I was looking for!

Did you manage to remove the pump after first removing the 4 hex head screws?