Volvo XC90: Specifications / Transmission fluid specifications
Under normal driving conditions, the transmission fluid will not need to be
changed during the transmission's service life. However, it may need to be changed
if the vehicle is driven frequently in adverse driving conditions.

Engine oil of type VCC RBS0-2AE 0W-20 must be used. Lower oil grades may not
offer the same fuel economy, engine performance or engine protection.
Volvo recommends:
General
See the Service and warranty booklet for information about oil change intervals...
The medium in the hydraulic brake system is called brake fluid and is used
to transfer pressure from e.g. a brake pedal via a master brake cylinder, which
in turn actuates the brake calipers...
Other information:
Gear position is selected automatically to make driving as energy efficient
as possible. The transmission also has a manual mode.
The transmission is available in two different versions. The gear selector indicates
which transmission the vehicle has...
A more economical driving style can help lower fuel consumption.
Before driving
If possible, precondition the vehicle before driving.
If preconditioning is not possible when it is cold outside, use seat and
steering wheel heating first. Avoid heating the entire passenger compartment
to reduce the amount of current being taken from the start battery...