Don032003

I bought a 2024 gmc 6.6 gas last year I have 30,000 miles. it started shifting hard around 3000 miles. It’s 7-8th gear when it happens every time it shifts. the dealer has reprogrammed it 3 times but comes back after about 1000 miles. This is getting ridiculous they say there is a service bulletin but there is no fix. I drive a lot and I’m so sick of the little jolt every time it shifts does anyone else have this problem ?