1st to 2nd gear shifts made a clunk sound when it was new and was a known manual tranny thing - not sure if you are talking about the same clunk but I no longer have it.

If they have another manual on the lot then drive it to see if it is the same, if not then replace it.

-marc

p.s. this video will turn your stomach:

http://www.sleepy-fish.com/sleepy/To...ossfire_hi.wmv