I'm finding it difficult to find information on:
- Transmission fluid intervals, type and steps to change.
- Front differential fluid intervals, type and steps to change (if applies).
- Rear differential fluid intervals, type and steps to change.
- Transaxle (I assume it has one) same as above.
- Radiator fluid interviews, type and steps.

Anyone know of write-ups for any of the above?

 

usually this stuff is found in the VIDA software for shops to follow. As to service intervals start with the factory guidance. The only service interval it calls out is oil changes at 10K miles and replace the brake fluid at 40K miles. All else is check level/inspect for leaks...

https://volvo.custhelp.com/app/manua...019/model/XC90

As general info newer transmissions have their fill level set at a specific temperature vs a dip-stick so you'd need a scanner capable of reading the transmission temperature in real time. There's a lot of opinions on when to replace the transmission fluid - some say 50K miles others say 100K miles. Considering Volvo doesn't say when yet the dealers offer this as a recommended service its your call - either should be fine (I'm in the 100K camp...). As to fluid types, check the owners manual or go to a Volvo dealer store to find the Genuine part number then google for compatible brands/specs. You can also browse Volvo friendly stores like IPD and FCP Euro to see what they recommend. General recommendations for the coolant is to replace/freshwater flush every 5 years - There may be additives as well that a dealer would recommend (again you can check in with a dealer web store). Some engines have a bleeder valve to help "burp" the system - I'd check Youtube for some vids appropriate to your engine. As to the differentials, generally they use a synthetic GL5 gear oil but since these don't take a lot of fluid it may be simplest to just buy Genuine Volvo. Note these generally don't need servicing so again this may be something you do at 100K miles.
The one thing to add to your list is power steering fluid. This is one thing where I'd recommend going with Genuine Volvo fluid or a direct replacement. Older power steering pumps just used hydraulic fluid or even spec out transmission fluid (My wife's Hylander specs Dex III for the PS!). Newer cars with electric PS pumps use a much lighter oil so that's where I'd stick with the genuine part. I don't bother opening the lines at the rack, I simply do a drain fill from the reservoir using a turkey baster and hose to suck out as much of the oil then refill with new, run the car turning lock to lock, then repeat. Generally you only need 1 quart to get 3 or 4 refills and that will take you to 90% fresh fluid... Again search Youtube for vids.

 

Found this on a Volvo dealer site. No reference to Transmission Fluid but good reference material

Maintenance schedule