Finally, that day come...Haldex oil and filter change...I already change rear differential and front transfer box oil- this is final chapter in 4x4 trilogy!
I was really anxious, hearing all that 4x4 malfunctions (mostly do to oil has never been changed- fill for life), and recalls for bad seal(not mine) and unadequan filter (mine)...
Seeing what others took out I was really surprised with state of mine oil after 126.000km...It was dark, with shavings of metal but no greasy stuff or chunks of dirt. I'm probably not aggressive driver and rarely driving in "sport" mode- which transfer power to rear axle.

So let's get started...first you need Haldex clutch oil for gen IV and set with filter and gasket.
OIL: GM 93165387 1940057 1L...very expensive
replacement 20-30eur, some 1L some 850ml:
Borg Warner 2000884 (owner of Haldex since 2011, so this is genuine too ) for gen II, III, IV and V (gen V is backward compatible)
VW G055175A2 for gen IV 1L, for gen V it is G060175A2 850ml
FEBI 101171 gen IV 1L, for gen V it is 101172 850ml
Volvo 31367940
FILTER set GM 20986573 40-70eur
BorgWarner 2006273

Raise car. It should be leveled, but if you want shorter version for filling rear right wheel should be higher then rest.
Loosen check plug with 8mm allen/hex key and check oil level. It should be at level with hole. Mine was 3mm lower.

I remove clutch cover WITHOUT lowering axel, but it was very difficult, you can see on pic there is little room for accessing top bolts.
I used this tool:

If you need to lower rear axel for more room to work, use jackstand to fix clutch assembly, then remove 2 bolts(think 18mm socket) from behinde, then 2 more from beneath. I prepare M12 bolt 20cm, to replace original from beneath, so I can fix assembly and lower it by unscrewing nut on that 20cm bolt.

Use cloth and clean around cover so no debrief fall in clutch.
Remove 10pcs 4mm allen/hex screws, holding cover. I had most difficulty with two on top and one in hole...good thing is they aren't tighten, and when loosed could be unscrewed with fingers, very easily...

Remove cover and gently pull while pushing vent hose with big flat screwdriver. Now cover is removed.
It was painful job, so I didn't take pictures. But, rest is no problem...
Remove old gasket and pull out old filter.
Clean cover, all dirt in clutch and white plastic filter on pump(can be removed with torx). If useing brake cleaner dont spray it on pump, presssure charger(top right corner) or in filter socket. Dirt is mainly in oil chamber, lower left portion where check hole is.

Pic from net

Oil oring on new filter and put it in place. Put new gasket on clutch. Take cover and put two top screws in place, also one in hole-if axle is not lowered.

Push away went hose and gently put back cover in place. Weegle cover while screwing top bolts with fingers just to stay in place. Do this for the one in hole. Now put all screws in place but dont tight them. When all screws are in place start tightining them in star pattern(up right, low left, low right, up left and so on...) to 6Nm.
When all are tight, push vent hose back and put it on vent pipe, it should slide on. Pull it if needed.

Now fill part...
GM tech document state that filling is done through vent pipe(with hose off), but can be done through check hole. Unscrew check plug (allen 8mm) and fill oil until it pour out. Plug hole and start car for 20 seconds so pump activate. Turn off engine, unscrew plug and fill it until oil pour out. Put plug back.
I fill it with 230ml and 100ml more for second time. 330ml in total, same as old...

Test drive it and check for leaks. It would be good idea to check oil level after some driving.