My Dad has an ’03 Chevy z71 Silverado 5.3 with the 4l80-e transmission that has the transmission clunk problem that Chevy is calling “normal”. It has been to the dealer 4 times and they reprogram the computer and the problem goes away for a few miles and then comes back. I know this problem is not normal because I have driven several other identical trucks that shift like silk. I bought an ’04 last week with the same transmission and it shifts no problem. Everywhere I look online I find people with the same problem but no one seems to be able to explain what is actually going on with the transmission. Dad has 6k miles left on the warranty so we need to figure out what’s going on before it runs out. Any ideas?