I have a 2006 s60 AWD with 213k miles on it. So far I have had lots of work done by an excellent mechanic to get the car to stage zero, maintenance wise. My question - and tell me if I'm incorrect - is does my car have two separate fluids on the rear diff (haldex fluid for haldex, then gear oil for diff), and then one at the front axle (angle gear)? Is this correct? Little by little I'm changing all the fluids and wear items on the car for peace of mind. Just to share, in the last 2500 miles of ownership I've had the following completed:

Synthetic Oil Change
PCV System Overhaul (OEM and IPD kit)
Transmission Fluid Drain/Fill (Volvo Fluid)
Timing Belt & Water Pump and tensioners (OEM Volvo)
Front Control Arms R&R (OEM)
Front Strut Mounts and all parts above struts R&R (OEM)
Drain & Fill Haldex Filter & Diff
Front Sway Bar End Links (OEM)
Trans Torque Mount R&R (OEM)
Main Coolant Hoses and Coolant R&R (OEM Volvo)
Thermostat Replacement (Bosch)
Turbo Hose Ends R&R (silicone IPD)
Radiator Replacement (Nissens)

Any recommendations on things to do, small things I could add to this list in addition to the above question about the different fluids in the driveline? Upgrades (shadetree DIY or professionally done - either work for me) that make sense from a stock standpoint or slightly better that will make things more reliable / predictable as well as perform for the long run are most appreciated.

Haldex is separate from the rear diff. The rear diff should be flushed with synthetic, of course. I would pull the fill plug and check the color first.

The angle gear fluid tends to 'cook' or overheat and should be flushed and filled.

The car is only 14 years old, but check the engine/tranny mounts anyway.

Do NOT over maintain. Enjoy driving it. Don't let the car sit for a week or two, they don't like to rest. Take longer trips than 10 minutes, the engine oil needs to heat up. Occasionally, down shift and get there revs up to 5,000 when the engine has warmed up.
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Keeping it running is better than buying new

Klaus - thanks for your response. I agree with not over maintaining - the thing was my car was - besides oil changes and fluid top ops, and newer tires, brakes, etc - not really paid that great of attention when it hit its second owner for about 30k miles or so. The PCV was near clogged, the radiator was starting to crack, the thermostat was beginning to leak, and the OTE turbo charge hose ends were squishy. My tech replaced a worn engine mount, and I'll be having him replace all the rest. It turns out he already replaced the rear diff fluid and we did the Haldex filter (haldex filter was dirty, fluid was clean). Control arms and end links and strut towers were toast. Radiator hoses were slightly squishy so replaced. PCV system was replaced in its entirety with an IPD kit. Timing belt and water pump were nearing the end, so we replaced them for good measure.

The car actually gets slightly better MPG and doesn't smell as much after turning it off. The engine bay is definitely cooler than when I first got the car and drove the first couple thousand miles. It also feels like it shifts smoother (we replaced pretty dirty but not spent trans fluid).

I appreciate your help - and usually every time I drive it's 10+ miles, and I hit the highways around DC where I live.

Thanks for the advice!

-Webb