I serviced all 3 of these fluids on a 2005 S60 2.5T AWD.
Or a siphon pump, but the siphon can’t reach to the bottom of the units. None of the 3 units have a drain plug. Many use a larger mityvac, but obviously it is more expensive.
The angle gear and rear differential take the same fluid. It is GL5 75W-90 with extreme pressure additives (redline is recommended).
For the angle gear, the correct fluid level is to fill until fluid reaches the fill hole, then remove 100ml. Use the siphon pump to pump fresh fluid until full in while the rubber (or plastic if you use a mityvac) hose is in the unit to to lubricate it. This will allow the hose to glide out and not get stuck on the sharp pinion/ring gear teeth.
I extracted 700-750 ml from this. I dont know if it was overfilled. It looked like it was never even serviced.
Burnt gear oil
I did a couple drain and fills on this one. I used https://www.fcpeuro.com/products/75w90-gear-oil-quart-oil-57904 and https://www.fcpeuro.com/products/volvo-differential-fluid-change-kit-liqui-moly-lm2048kt
For the rear differential, the correct level is to fill until fluid reaches the fill hole, then remove 50ml. Same goes for this with pumping fluid in until full while the hose is still inside. I extracted 750-760ml from this, but it was overfilled and started leaking from the vent when i refilled it. Amsoil website says fluid capacity is .71 liters.
I replaced this rear diff fluid with https://www.fcpeuro.com/products/volvo-differential-fluid-change-kit-liqui-moly-lm2048kt
Alternatively, Something like This could be used. Bmw differential fluid extractor tool for sealed differentials.
This generation haldex (2) either has a special level setting procedure or it’s fill until it reaches fill hole, then you’re done. The special procedure would be to fill until fluid reaches the fill hole, put plug back in, go for a drive, fill unit to fill hole again, then remove 40ml. Those are the instructions for gen 3 and 4 haldex which also use a filter. I extracted 450-500ml using the fluid transfer pump.
Extremely burnt. Fresh fluid has a yellow hue. I used https://www.fcpeuro.com/products/volvo-aoc-haldex-gear-oil-1-liter-31325136
source: https://www.yetiownersclub.co.uk/threads/haldex-oil-change.10920/
Changing the haldex filter is a huge annoyance because there is such little space for tools behind the AOC oscillation damper.
Torque specs for the three fill plugs is 35Nm. I found that a 1/2 inch socket fits better than a 13mm.
https://www.swedespeed.com/threads/complete-fluid-change-how-to.81428/
this thread has similar procedures