Volvo Repair: S60 T5 Auto gear transmission, gear transmission, careful notes

Question
I bought this model brand new in February 2003, recently I begin to felt a kind of "tud" from the down gear shifting when I am slowing down at around 800 to 1100 rpm. It mostly happen when I am slowing down at traffic light than allowing it to glide.. and stop. I went to the agent, they say it is duwe to the software and they down load the soft ware. But after a few days later it happen again occasionaly. Feel like when it shifts down from 2nd to 1st gear, but there is no problem when accelerating. can you enlighten me what could be the problem?

Answer
Well the throttle bodies on those cars have a tendabcy to get dirty which will cause the idle to drop too low while coming to a stop.  I would try cleaning that next because it's easy and cheap.  If that does not help at all I would start taking careful notes of the times and conditions it happens.  As soon as you can figure out how to replicate it consistently then the shop should be able to find the problem.  It could even be a transmission starting to fail.  So if you are about to go out of warranty be sure to get back into the dealer and make another complaint because if you make a complaint about it under warranty, they say that there is nothing wrong with the car and give it back to you, and then it goes out of warranty and fails; they should be obligated to fix it under warranty because they were aware of it befor it expired.  

James