Seems like if you have the T6 AWD your doomed from the beginning with transmission and electrical problems. I picked up a 2004 2.5 5-cylinder with 80,000 miles and a blown motor at my local Volvo dealer for $2000.00!! Volvo had just installed a new transmission in it about 2000 miles before I bought it under warranty. I Called LKQ and they delivered a fresh 40,000 mile engine to my front door for $800 including shipping! Before I dropped the engine in, I installed a new timing belt water pump and replaced all the oil and coolant seals. Took about 3 days of wrench spinning and I now have a perfect 1 owner 2004 XC90 2.5 AWD with 80,000 miles for about $3200!!
I'm glad I'm not the poor sucker that spent $40,000 dollars for this SUV. I've owned it for 2 years and put additionally 30,000 miles on it. Not one problem and totally trouble free!! Do your regular maintenance, keep the oil clean and service the transmission with the Volvo Synthetic fluid and your XC90 will be totally trouble free!!