2007 XC90 squeak

I love my XC90 with 180k miles. Bought it with 101k miles and replaced the alternator and battery at 140k miles. Recently oil changed, replaced ignition coils, shocks, brakes, brake hoses, struts, right rear hub bearing, one of the 4 catalytic coverters, flushed transmission fluid, and flushed coolant system. Hopefully I'm good to go for a while, like I said I love the car. Get 17 mpg city and 25 mpg on long highway trips.
Problem is I get a clunk/squeak when I go over a rough road. Mechanic and I are at a loss. Any ideas?