Noises During Shifting problems of the 2003 Chevrolet K1500

I have a 2003 K1500 Chevrolet silverado with an automatic transmission that has a severe clunking noise when shifting between 2 and 3 gear. Chevrolet acknowledges the clunking sound and gave me a document id#1828818 which states they have a problem but no solution. I have contacted the dealer I purchased the truck from and another local dealer since with my first visit on 12/17/04 at 14444 miles with the clunking noise progressively getting worse. I have been told by both dealers on every visit that Chevrolet will not repair nor replace the transmission. Please help.

While shifting gears driver heard a loud clanking noise coming from the front. Vehicle was taken to the dealer for inspection, and mechanic determined that the computer needed to be reprogrammed, and reprogrammed it three times. However, the problem recurred.