When cold I notice a clunk sound when shifting from first to second gear. This is more pronounced when engine is cold. Any thoughts as to the source of this problem?

 

1st. to 2nd. gear shifts on a cold transmission are usually described as being hard, stiff, or notchy. Can't say I've heard anyone complain about a clunking sound though.
Does the sound seem to resonate from the transmission, or is it possibly coming more from the differential? (they are both so close together, it may be a little hard to determine).
After the car warms up, does the "clunking" seem to go away?

 

I do feel some resistance going into second gear and it is not very noticeable when warm. As the weather had become cooler it is more an issue. I have only had the car for about 6 weeks it has 48K miles. Would changing to a synthetic trans oil be of any help?

 

The car comes from the factory with ATF III, and at my cars 36k check up the tech. installed synthetic Motor oil. I never really felt much of a difference. But I do feel the motor oil lubricates the tranny parts better than the ATF.
Most all of the manual transmission Crossfires seem to share the "notchy" 1-2 shift, Some are worse than others. Many feel it's less noticable if you're more aggressive when shifting. (Like taking it up to 3 or 4k in first gear, then shift). It's not very condusive to improving fuel mileage, but some feel it shifts better that way.
As I've said before, I've owned over 2 dozen different sports cars with manual shift, and the Crossfire is the worse shifting transmission I can remember. At least the 1-2 shift is. That being said, I still love it.
It just takes awhile to get use to.
Good Luck