I'm in Canada (Toronto) with all the cold snowing winter. I say this because my wife had an incident that similar to your problem.

In a cold winter afternoon after a whole day's work, she started up the car and try to backout of the parking, like you it clunk but no motion, she tried a few times; back to P and then R. Call me and the dealer with no help. Call our mechanic friend who is a car racer. He said it is usual (in cold weather) that the oil pressure in the tranny that is not balanced. He preciselly told my wife to put into 'N', wait for a few mins., let the oil pressure build up and balance itself, so as to push and pull the gears. It works and has no permanent damage to the Volvo so far.

If you have the problem again try this method before you spend you money.

Good luck.

Peter Chiu