I have a 2023 GMC Sierra AT4 with 3.0 Duramax and my truck has been in the shop since 12/5/23. The truck has 10,000 miles and is leaking transmission fluid. I stopped driving it as soon as I noticed the leak and towed the truck to the dealership. They replaced some washers at the thermal block and it still leaked, they replaced the thermal block and it still leaked and now they are replacing the cooler lines. Not real impressed. I never had any issues with my Ram Hemi.... Looks like I will be getting a Ram 2500 Rebel.