First time changing transmission oil on my 2009 Volvo XC70 T6, it has 60,000km or 37,000miles.
You need VIDA and DICE to complete this job properly. You can get it on Ebay for around 100USD.

Total capacity of oil in the transmission is 7 liters.
This will be same on diesel and petrol Volvo using the TF-80SC Transmission.

Please check with your dealer for correct oil type!!!
From 2000MY to 2009MY Transmission oil part number is 1161640
From 2010MY to current: Transmission oil part number is 31256775

Hex 17mm washer is 30713220
Torx - 40 Black O-ring is 1233068

Level tube - 31325038
Plug small for level tube - 30713219

The car is level! There is a slope in the garage floor.