I just purchased a used 2008 S40 with 92,000 miles on it. It seems to have been well cared for. But, as I drove it off the dealer lot, I noticed a slight (soft) clunk as it shifted from 1st to 2nd gear. I drove it the next few days listening for this sound. What I deduced is that it would only happen the first time the car shifts from 1st to 2nd. As long as you were driving, it wouldn't happen again. If you turn the car off and leave it for a while, it would happen again when you first drive/accelerate from 1st to 2nd. After listening and experimenting with different variables, I noticed it didn't always happen at the exact time the transmission is shifting... it seemed to happen closer to the time the transmission hit 2000 RPMs. If you accelerate very slowly, the car could shift into 2nd gear, and then the sound would happen at approx. 2000 RPMs. It's a hard sound to describe. It's nt a loud clunk, but a medium to soft "ca-chunk". The dealer who sold me the car and a local Volvo dealer both heard the sound... neither can identify it.

Thanks everyone!!

Bob